How the CPU Manager Decides

01. How the Odds Work #

Most CPU moves take two steps. First the game situation has to call for the move: the right inning, the score close enough, the right runners on base. Then a random roll decides whether the manager actually makes it. A sacrifice bunt with a runner on first, nobody out and a close game is called 30% of the time at the standard setting, before era scaling. A few moves have no roll and happen every time their situation comes up, such as bringing the infield in with the tying run on third late.

Era scaling. The CPU reads the real numbers of each team's own league and season: runs per game, relief appearances, saves, pinch hits, pinch runners, defensive replacements and sacrifice bunts. A move that league made less often than a modern club is rolled at a lower chance in proportion. The 1908 American League used relievers about 13% as often as a 2010s club, so a lefty/righty bullpen move a modern manager makes 65% of the time is made about 9% of the time. No season is scaled above the modern rate, except the bunting and hit-and-run chances of leagues that really bunted more.

One roll per moment. Each decision is rolled once for its moment: once per pinch-hit chance per batter, once per run a struggling pitcher allows, once per runner's stay at a base. The manager looking at the same spot again doesn't get a second try.

Real-season pace. In a season, many decisions also compare each player with how he was really used that year: his starts, complete games, relief appearances, saves, pinch hits and intentional walks. A player well ahead of his real pace is passed over and one behind it gets the call, so season totals land close to the real ones. "Real pace" on this page means a player's real total times the share of the schedule played so far.

Which era a team plays in. A historical team plays by its own league and season. A drafted team uses the middle season of its players' real seasons. In a cross-era game, each manager follows his own team's era.

Settings. Every number here is the standard setting. If you change the CPU Manager Settings, the era scaling still applies on top of your values.

Want to know more? Ask about any section in the forum .

02. The Eras at a Glance #

Each column is one real league season, at the standard settings. Every other season gets its own numbers the same way, from its own league's real totals. Swipe the table sideways on a phone.

* After the DH, the bunt chance is also raised or lowered by each batter's own real bunting habit, so a pitcher or No. 9 hitter bunts more and a cleanup hitter rarely does. In a season, every club is also held to its league's real number of pinch hits, apart from hitting for the pitcher after the DH arrived.

03. Rules in Every Era #

These rules hold for every season. The era sections below say how each era changes them.

1. Lineup Construction & Batting Order #

   The lineup is built from the team's real season, the same way every time.

   • Each position goes to the player with the most real games there, filled in the order C, 1B, 2B, 3B, SS, LF, CF, RF, then DH. A pitcher never fills a fielding or DH spot. Without the DH, the starting pitcher bats ninth.
   • Batting order: third goes to the best combined home run and batting average ranking, cleanup to the most home runs left, leadoff to the most stolen bases left, second to the best average left, then fifth through eighth by average. With the DH, whoever remains bats ninth.
   • In a season or a World Series, a saved lineup against right-handers or left-handers is used when the other team's starter throws from that side.
   • In an AL or NL season played with Real lineups and starting pitchers, injuries are off and each game starts the lineup each team really started that day. A real starter who isn't on the active roster is covered the usual way, and the game log says who took his place.
   • Rest days: each regular sits as many games as he really didn't start that year, spread evenly over the season. A player who really started every game never sits. The regulars who sat most in real life are covered first. Who covers depends on the era.

2. Starting Pitcher, Rotation & Rest #

   The rotation comes from real usage, the same way every time.

   • A pitcher joins the rotation if he started at least half as many games as the team's leader. The rotation is ranked best first by a score where ERA counts 10 times and WHIP 6 times against him, with a small credit for innings, starts and winning percentage. The top man pitches Game 1 of a series, then the rest in order. In a World Series, a rotation order saved on the Pitching Staff screen is used instead.
   • In an AL or NL season played with Real lineups and starting pitchers, injuries are off and each game's real starter takes the ball. When he isn't on the active roster or needs rest, the CPU's usual pick starts instead, and the game log says so. From the mid-1950s through 1972, a real starter who pitched that day or the day before, or started two days earlier, needs rest too.
   • Five starters on 4 days' rest. A team whose real ace started 22.5% of its games or more runs four men on 3 days' rest (24.5%, about 40 starts in 162 games, from 1973 on). Negro League clubs run three men on 2 days' rest. A drafted team always runs five.
   • A short staff is filled out with part-time starters before relievers. When a starter is hurt, a spot starter covers that one turn and the rotation moves on. A spot starter is always a pitcher: a man who mainly pitched that year or made a real start. A position player never starts a game on the mound.
   • In a season, a starter more than a quarter past his real starts, plus one, gives his turn to the spot starter furthest behind his own real starts.

3. Pulling the Starter & Bullpen Use #

   • Fatigue. A pitcher's limit is 16.5 pitches for each inning of his typical outing, never under one inning. A starter's typical outing is how far he went on days he wasn't knocked out. The manager lets him run 15% past it, give or take a daily roll of up to 15%, so he comes out somewhere between his limit and 30% past it. That roll is made once per pitcher per game.
   • Getting hit. At 5 earned runs (more in a high-scoring league: 5 times its runs per game over 4.5, rounded) the manager rolls to pull him, once for each run from there. The chance is how much the league used its bullpen against a modern club.
   • No-hitters. A starter who hasn't allowed a hit is never pulled. He is left in over the closer 95% of the time.
   • Lefty/righty moves. Relievers only, from the late innings through the 9th: when the batter has the platoon edge and another arm would take it away, the manager makes the move 65% of the time, scaled to his era's bullpen use.
   • At most one optional pitching change per half-inning. A pitcher who is getting hit can still come out.
   • Low-leverage spots. When the batter can't change the outcome (a lead bigger than the tying run's reach, or a deficit of 4 or more), there are no lefty/righty moves. A reliever's limit stretches 30% and nobody is pulled with two out.
   • Picking the reliever. The closer comes in only to protect a 1-3 run lead in his inning or later, or in a tie in his inning or later. In the postseason he can also come in late trailing by a run. Among everyone else: arms with 2 or more days' rest first, then whoever takes away the batter's platoon edge, then the lowest ERA.
   • Workload. No reliever pitches a third straight day (a closer may) or a fourth time in 7 days. In a season, a reliever more than a quarter past his real relief appearances, plus two, is skipped.
   • Assigned roles. At the start of the 9th with a 1-3 run lead, the closer comes in if he hasn't pitched: the assigned closer, or else the saves leader once teams had closers. When the 8th is tied or within a run and the assigned setup man has given up a run, the closer comes in early. From the 7th on, down 5 or more, the assigned mop-up man takes over.
   • All-Star Game. Each pitcher works one inning and the bench starts coming in from the 3rd.

4. Pinch Hitting, Pinch Running & Defensive Changes #

   • Hitting for the pitcher (no DH). A tired pitcher due up is hit for in any inning. From the 7th, a pitcher whose team is tied or behind is hit for at the era's pinch-hit roll. A closer or setup man protecting a 1-3 run lead keeps batting. The manager keeps his pitcher in when no rested arm is left to replace him.
   • Hitting for a regular. Late in the game, a bench bat with at least 20 at-bats needs a batting average 40 points higher with the platoon edge, or 80 points higher without it. The 3rd through 6th hitters are hit for only from the 9th on, within a run, by a bat 80 points better. The pinch hitter has to be able to play the position afterward. A bench pitcher is used only when no position player is left.
   • Pinch running. Late, within 2 runs, when a bench player had at least 8 more real stolen bases than the runner. Stolen bases stand in for speed. He has to be able to play the runner's position afterward. From the mid-1950s through 1972, any faster bench player will do from the 7th, held to the league's real pinch-run total.
   • Defensive changes. Late with a lead. A fielder who is out of position or a poor glove there is replaced when the bench has a sure glove who can cover. Otherwise a bench fielder whose error rate at the position is at least 15 points lower (say .990 against .975), both with 30 or more chances there, comes in, two such changes a game at most. The last bench catcher stays put. A glove man who came in late is never replaced himself. Without the DH, the same swap can ride along with a fresh pitching change as a double switch.

5. In-Game Strategy #

   • Steals. Each runner goes at his own real attempt rate per time on first (singles, walks and hit by pitches, 87% of them with second open). 12% of his attempts are steals of third, rolled on his times at second with third open. One roll per runner per stay at a base in an inning. A runner being held goes 60% as often. The CPU doesn't call steals of home or double steals.
   • Pickoffs. The CPU never calls a pickoff throw. Whoever manages, a pitcher throws over to first at his own real rate, or his league's rate for his throwing hand, and a throw gets the runner at the matching real rate, adjusted for the runner's speed. A left-hander's throws to first get the runner far more often.
   • Squeeze. Runner on third, fewer than two out, late, within a run: called at the sacrifice chance.
   • Sacrifice bunt. Nobody out, a runner on first or second, third base open, close game: 30%.
   • Hit-and-run. One out, a runner on first with second open, close game: 25%. If the batter strikes out, the catcher throws on the runner. From the mid-1950s through 1972 he doesn't throw on a runner who seldom stole.
   • Batting approaches. Sacrifice Fly Approach 35% (runner on third, fewer than two out, close game). Hit to Right Side 30% (runner on second, third open, nobody out, close game). Put the Ball in Play 35% (a hitter who strikes out 20% of the time or more, a runner in scoring position, fewer than two out). Work the Count 30% (a starter 75% of the way to his limit, or a hitter who walks 10% of the time against a pitcher who walks 10%). All but Work the Count scale with the era's bunting.
   • Infield In. Runner on third, first base open, fewer than two out, late, close game: every time.
   • Other defensive calls, in games played or watched pitch by pitch: Infield Halfway 60% (runner on third, fewer than two out, within 4 runs), Corners In 60% (nobody out, a runner on first or second, close game, the pitcher or a real bunter up), Outfield Shallow 60% (the tying or winning run on second late, or a hitter with extra base hits in under 4% of trips), Hold Runner 85% (second open and a runner who tried to steal second 10% of his times on first or more).
   • Intentional walks. First base open, a runner in scoring position, late, close game, when the batter hits .300 (.280 with the platoon edge) or 60 points better than the man on deck, both with 20 or more at-bats. In a season, the league's real intentional walk count takes over: past it, nobody is walked, and short of it, anyone who outhits the man on deck is. From 1955 through 1972 and from 1990 through 2022, a season walks each hitter at his own real pace instead, in any inning.
   • Running the bases. The CPU sends a runner when his odds are 65% or better, adjusted for the era's outfield arms. Tag-ups follow real attempt rates, including on a foul fly an outfielder catches. On defense it throws home whenever the runner's odds are 95% or lower. Late in the game it also throws home whenever his run would tie the game or put the other team ahead. On a ground ball, the infield throws home at 80% or lower.

   "Close game" means within 2 runs either way and "late" means the 7th inning on, before era changes.

6. Roster Moves #

   Season play only, between games. The CPU makes these moves for every computer team. It makes them for yours too when the season's automatic roster moves setting is on. Being tired is never a reason to send anyone down: a tired player sits a day on the active roster.

   • Relievers. Optioned after at least 15 innings with an ERA 1.75 times the league's so far or worse (about 7.00 in a 4.00 league), worst first. The closer and the rotation are never sent down.
   • Position players. Optioned after at least 40 at-bats hitting 0.6 times the league average or worse (about .155 in a .260 league), worst first. A regular, averaging 2.5 or more at-bats a game, rides out his slump.
   • The best available player from the team's real season takes the open spot. Two swaps per team per day at most. An optioned player stays down at least 15 days.
   • Injuries (when the season has them on). Every player who appears in a game has a 0.35% chance of getting hurt, plus 0.025% for each year he is past 30, up to an extra 0.6%. A hit by pitch adds a 2% chance on the spot. 65% of injuries are day-to-day (1-6 days), 30% short-term (15-45 days) and 5% end the season. When a longer injury opens a roster spot, a computer team calls up a replacement: a player who played the same position, or the arm who pitched the most for the team that year (a starter when a rotation arm goes down). Your own team's call-ups are always left to you.
   • Over the limit. A returning injured player or the postseason limit dropping from 40 back to 30 can leave a team with too many active players. A computer team sends down whoever it has used least this season until it's back at the limit: a pitcher when the staff is bigger than its usual 13-of-30 share, otherwise a position player. The rotation, the closer and anyone a position would be left without are kept. Ties go to the most recent call-up. Your own team's next game waits until you make the move.

04. Era by Era #

The years below are where the engine's behavior changes. Some edges come from each league's own numbers, so a league can cross one a season or two before or after the other.