MLB Elo Ratings

MLB Elo ratings

Team strength ratings updated nightly, split by the handedness of the pitcher a lineup is facing, alongside pitcher strikeout ratings. A team is not one number, and a rating that ignores who is on the mound describes a team that never actually plays.

How Elo works and why it suits baseball

Elo adjusts after every game based on the result and the quality of the opponent. Beat a strong team and you gain more than you would beating a weak one, and the rating moves toward the truth over a season without anybody deciding how much to weight anything by hand.

It also decays naturally. Recent games matter more than old ones, so a rating reflects the team as currently constructed rather than as it looked in April. That is useful in a sport with trade deadlines and long injury absences.

The reason it needs splitting in baseball is that lineups change shape depending on the starting pitcher's hand. A lineup built around left-handed bats is a genuinely different offence against a lefty, and a single team rating averages those two teams into one that does not exist.

Using ratings against a market

The practical use is converting a rating difference into an expected win probability and comparing it to the moneyline. That comparison is only worth acting on when the gap is large, since the market prices the same information and usually prices it well.

Elo is weakest exactly where baseball is most unpredictable, which is any single game. It describes team strength over time, and a single start from a pitcher having an unusual day overwhelms it. Treat it as a season-level input rather than a game picker.

Frequently asked questions