Making Baseball Pythagorean Expectation Work Against the Betting Odds

Marcus Semien #10 of the Toronto Blue Jays celebrates a home run with Vladimir Guerrero Jr. #27 against the Minnesota Twins. Mark Blinch/Getty Images/AFP

One of the great aspects of betting baseball is finding elements that send you in different directions. Being able to determine what is important and what is not.

That’s why examining various ideas or theories allows you to expand your thinking, with the intent of making you better when wagering against sportsbooks.

We just started the second half of the baseball season and we will take a look back to look ahead for the rest of the season. It is a given that nobody knows how each team’s last 81 games will work out after playing 81 times in the front half of the season. With injuries, roster moves and the trade deadline, that is just a few aspects that will help formulate how the rest of 2021 will find its final resting spot.

However, Pythagorean Expectation, created by the inventor of sabermetrics, Bill James, gives us a peak for those of us who study the betting odds at OddsTrader on what could happen in the second half of the season.

The idea is relatively simple. Take runs scored + runs allowed and generate a total. Next, divide the runs scored into the total and you will have a percentage. Take that percentage times 81 and that tells you how many games a team should have won among their initial 81 contests or half the season.

Next, compare that figure with the actual record of any team and any discrepancy of more than 2.5 games which should be looked into.

Below is a chart for each team that supplies all the answers. After looking at it, we will attempt to formulate some answers for you.

TeamsWLRuns ScoredRuns AllowedAppx. WinsAppx. Losses
Red Sox503141036243.537.5
Blue Jays433842234844.536.5
White Sox493240430346.234.8

Teams That Could See Regression

Let’s start at the top. Boston has outperformed its numbers to this point. The Red Sox are solid across the board both home and away, but unless they start winning more decisively, winning 100 games seems unlikely against the MLB odds at OddsTrader.

Oakland has been more clutch than stellar to this point and unless they get bullpen help and make a trade for an outfield bat, it sure seems they could fall behind Houston in the second half.

Milwaukee and the New York Mets had scoring problems most this the first of the season and survived on great pitching. Each is in divisions that they could win on almost pitching alone, but if someone steps up, they could become Wild Card material.

Technically, the Giants and Dodgers are behind on run differential. Nevertheless, playing Colorado and Arizona in the NL West and several more National League teams outside of San Diego, who are playing pedestrian baseball, they could hold their positions. San Francisco is more likely to slide back.

Teams That Could See Improvement

This year, several bottom feeders are capable of improving as you can see. If you consider Baltimore, Arizona, Colorado, Texas, and Minnesota should get better, what is holding them back? Poor relief pitching. These clubs can hold one or two-run leads going into the 8th inning and time and again they lose by a single run. Could that change, possibly, just hard to see how at this time.

Pittsburgh and Miami have above-average pens and if they can score more runs in their mediocre divisions, they could be a very live underdog in the second half.

Always Consider This

There are no absolutes for placing MLB picks. Every year, there is a team or two that far exceeds expectations and could reach the playoffs with a run differential of under +20, but wins 88 or more games. (Note: These teams are typically Play Against material the following season as overachievers)

For this exercise, Seattle is a perfect example. The Mariners are 4.5 runs above expectations and having a 19-7 record in one-run games explains why this happened. Will this or should this continue for the M’s? No, however, some years it does. (If you notice Seattle starting losing these kinds of contests, you know what to think.)

This is primarily a guide, something to be aware of when studying the baseball numbers at OddsTrader. Increased knowledge can and will make you a smarter and more skillful sports bettor and here is one more tool that enhances your skills. is your sports betting command center. Read featured betting strategy compiled from a panel of leading sports betting experts.

Site Footer