Introducing xxWins: A New Way To Forecast MLB Team Success

Recently, I introduced the award index, a tool that will allow us to better project individual success/award winners. However, as mentioned in the piece, baseball is a team game. General managers aren’t trying to make moves to acquire as many award winners as possible. Rather, they’re making various endeavors to do whatever it takes to ultimately compete for a World Series championship, regardless of when that may be.

With that in mind, it is important that, as analysts, we are able to better project overall team success. Obviously, expecting teams to simply play as well as they have would be silly, but, by now, projections are much less meaningful. This creates quite the dilemma for us to sort through.

A common way that analysts assess a team’s legitimacy is by looking at their run differential, or, even more relevant, their pythagorean wins. Luck in one-score games can be deceiving and volatile, and, for this reason, pythagorean wins does a nice job of leveraging the amount of runs a team is scoring and allowing to assign them with an expected record.

However, in small sample sizes, or even a whole season, run differential can be deceiving. It isn’t just about the run differential, but how the run differential is formulated. That leads me to create a new projection metric: expected pythagorean wins, or xxWins.

We have analyzed in the past what correlates to overall team success between offense, defense, and pitching, and also analyzed each team’s overall luck in 2020 based on this thinking. While the original premise of the study was to try to find inefficiencies in team-building – it appears defense might be slightly overvalued – there is obvious predictive power to this. By utilizing Fangraphs‘ offensive runs above average, defensive runs above average, and pitching Wins Above Replacement (WAR) and incorporating the proper weighting system based on previous research, we can create a metric to forecast the rest of the success. In fact, going back through 2015, xxWins has had a higher correlation to xWins than team WAR has, which leads me to believe that it is effective in assessing the ideal makeup of an organization.

With this tool, the possibilities are endless. Who are the true best teams in the league currently? We already can understand which teams are outperforming their overall record, but about their run differential? Today, with this metric, we will answer all these questions, in addition to looking for values on the futures betting market. Let’s get started!

What Teams Have Overall Deceiving Records/Expected Records?

Overperforming Overall Record

  1. Cleveland (-21 Wins/162 Games)
  2. Chicago Cubs (-11 Wins)
  3. St.Louis Cardinals (-11 Wins)
  4. Tampa Bay Rays (-11 Wins)
  5. Seattle Mariners (-11 Wins)
  6. San Diego Padres (-11 Wins)
  7. San Francisco Giants (-11 Wins)

Overperforming Expected Record

  1. San Diego Padres (-20.5 Wins)
  2. Toronto Blue Jays (-14.4 Wins)
  3. San Francisco Giants (-14.2 Wins)
  4. Houston Astros (-13.7 Wins)
  5. Chicago Cubs (-11.7 Wins)
  6. Tampa Bay Rays (-11.7 Wins)
  7. Cleveland (-11.3 Wins)

There is some overlap on this list, though variance in one-run games makes it less than you’d expect by the end of the season. Cleveland is a very strange team to peg overall. They rank below-average in offense, defense, and pitching, yet continue to win games? I’m quite puzzled by this. Outside of them, the Cubs and Cardinals are the only teams projected to be closer to sub .500 teams than winning teams, with neither possessing a clear strength. Don’t worry about the Padres, for the record; they’re on pace for 111 xWins, making them a natural regression candidate.

Underperforming Overall Record

  1. Baltimore Orioles (+16.75 Wins)
  2. Chicago White Sox (+13.15 Wins)
  3. Minnesota Twins (+10.05 Wins)
  4. Arizona Diamondbacks (+10.02 Wins)

Underperforming Expected Record

  1. New York Mets (+15.4 Wins)
  2. Baltimore Orioles (+10.3 Wins)
  3. Oakland A’s (+9.65 Wins)
  4. Pittsburgh Pirates (+7.15 Wins)
  5. Milwaukee Brewers (+6.89 Wins)

I’m sure the Orioles aren’t complaining being in position for a top pick once again, though they have deserved better as a more well-rounded team than expected. Really, though, my fascination is with the Mets and A’s, who are both interesting case studies. Typical analysis that leans on run differential would indicate that both are regression candidates, but what if their run differential is also going to regress positively? The Mets have been a dominant team from a pitching standpoint, while the A’s are scoring runs with the best of them. Also, if the White Sox are in line to get even better, watch out.

Thus far, offense has been much more predictive of team success than defense than in the past (by almost two times), while pitching hasn’t been as significant as expected. Could this mean positive regression for teams proficient in run prevention, or a sign of things to come in an offensive-deficient time for the game? That will be exciting to monitor.

Power Rankings

Now, it’s time to establish adjusted win totals for each team, in order to get a read of where they stand compared to the league.

It is generally a poor idea to expect teams to play as well as they currently have, which means preseason expectations still have some significance. With that in mind, I’ll be regressing each team’s xxWin pace with their projected wins from Fangraphs. Thus, we aren’t only taking into account how well each team has played this season, but their likely true talent level, hopefully leading to the most accurate projection.

Most of this aligns with expectations. Of the surprises, the Red Sox finishing ahead of the Yankees is notable, but when you’re amongst the elite teams in terms of offense and pitching, that’s what is going to happen; it’s likely we need to come off of preseason skepticism of Boston. Also, by the end, the Dodgers likely will gain separation from the Padres in the NL West, while the NL Central and AL West will go down to the wire. Hopefully, this also helps demonstrate how dominant the White Sox have been. Not only is their offense and pitching elite, but their defense is also strong, and when all three facets of play are major strengths, you’re going to perform well. With a deep bullpen and strong front of their rotation, they are also a team naturally positioned to do well in the postseason, which adds some additional intrigue when projecting them as a potential World Series winner.

Division Projections/Odds

Now that we have looked at each team’s expected win total, let us put this tool to practice. Starting with each division, we’ll compare each team’s true chances of winning their respective division to where the betting markets have them at, hoping to find surplus value. A positive surplus value indicates that the team is underpriced relative to their true talent level, though that doesn’t simply make it a strong bet: understanding future market movement and the cost-benefit analysis of each potential bet is critical.

AL East

Right away, we start off with a very intriguing division to break down! The Yankees came into the season as the favorites to win the AL East, while the Rays and Blue Jays each made the postseason last year. Yet, it is the Red Sox that are projected to finish top in the division. Thus far, they rank top-five in the MLB in both offense and pitching; when that’s the case, you’re going to have a lot of success. The offense was expected to be very productive at the top, but it’s shocking to see them perform so strong on the pitching side of things. Is it that shocking though to see Nathan Eovaldi or Eduardo Rodriguez produce, though? Although, their rotation depth isn’t great, their bullpen shouldn’t be overlooked, while the expected return from Chris Sale will only help them further. In other words, the fact that they are being priced as a fourth-place team is absurd.

AL Central

Although Cleveland is only 1.5 games out of the AL Central, xxWins suggests they have dramatically over performed. To put it in perspective, their offense is equivalent to that of a 69-win team, while they don’t have to defense and pitching to overcome that. You could put a long shot bet on the Twins just in case, yet this division is convincingly in the White Sox’ favor. In reality, even at -345 odds, they probably aren’t getting enough respect.

AL West

Wow! That is quite the division race! Ironically, the Astros and A’s are quite different. Houston has the edge in current run differential and preseason expectations, but Oakland is likely to see their run differential get better. Intuitively, the Astros getting back Framber Valdez and Jake Odorizzi might end up giving them the edge here, but can’t the same be said about the Athletics’ pitching reinforcements? This is going to go down to the wire, making it not viable from a betting perspective.

NL East

This is the only division where all five teams have a viable chance of winning. As we discussed, run differential is underselling the Mets, and they have been destroyed from injuries. The real discrepancy here is Atlanta compared to the other teams. They’re essentially on par with the Phillies and Marlins currently, and the Nationals should get better. You could look at Philadelphia’s odds, though I’d much rather get much more favorable odds with Miami and Washington. Remember, the Marlins are the only team in this division with a positive run differential currently, while they are currently the second-best team in this division, based on xxWins.

NL Central

With where the top-four teams are projected to finish, the current division odds are certainly improper. The Cubs are currently tied for first place in this division, though they also are projected to regress based on xxWins. However, we need to find a way to fade Cardinals and Brewers. That leads me to the Reds. With the second-best offense in the division, they should be performing better than they can, and still have a 9% chance of winning this division, per Fangraphs. I am even higher on them than that, based on xxWins, especially since their defense hasn’t been as poor as anticipated. Sure, it’s not an extremely likely outcome, but significantly more than +1450 would suggest.

NL West

The betting markets see the NL West as a two-team race, as they should. Still, for an 86-win team based on projections, it is tempting to take the Giants at +1800. They’re only 1.5 games out of the division, have performed well against the Padres, and you never know what could happen if variance goes their way. Their ability to try to be competitive with the Dodgers this weekend will be critical in assessing their odds.

  • Bets To Make: CIN To Win NL Central (+1450), BOS To Win AL East (+438), MIA To Win NL East (+1325), WSH To Win NL East (+1650)
  • Bets To Monitor: SF To Win NL West (+1800), CHW To Win AL Central (-345), CHC To Win NL Central (+544)

Pennant Projections/Odds

American League

The Yankees remain the betting favorite to win the American League, but the White Sox and Red Sox are currently projected by this methodology to finish ahead. Really, you would want to fade New York when possible, making Chicago, Boston, and Tampa Bay all worthwhile bets. Betting the Rays, however, following an 11-game winning streak, would appear to be buying them at their highest point, which is not what you want to do. Outside of that, no other options provide any value at this current moment.

National League

The National League is a much more condensed than the American League. Really, it’s the National League West and maybe the Mets, though the Dodgers remain the obvious favorites. Although you could look at the Giants here – +1867 is way too high for a team projected to make the postseason – there isn’t much value to be had here.

  • Bets To Make: N/A
  • Bets To Monitor: BOS To Win AL (+867), CHC To Win NL (+2833)

World Series Projections/Odds

This is the much better spot to buy into the Red Sox, as their World Series odds aren’t congruent with their pennant odds. Furthermore, the White Sox aren’t going to be not seen as a favorite for much longer should they perform as well as xWins suggests they will. Outside of that, this is a better spot to invest in the Giants, though it still feels like you’re buying them at their highest point. Remember, even if there’s surplus value with a bet currently, we need to try to forecast the market to maximize on the ultimate opportunity.

  • Bets To Make: BOS To Win WS (+1800)
  • Bets To Monitor: CHW To Win WS (+833), SF To Win WS (+3600)


Run differential is a great tool to assess the validity of a team’s overall record. However, especially in small sample sizes, finding out which teams are accumulating their run differential in the most sustainable way possible is important. That’s where xWins comes into plays. Utilizing this tool, we can get a true sense of the talent level of each team. From there, by incorporating projections that can take into account preseason expectations, an ideal method is formed to forecast future team success.

Using this tool, the Red Sox, Marlins, and Giants stand out as clear undervalued teams, though the latter case is interesting considering they have overachieved in every category. Other than those two, the betting market appears to be higher on the top of the NL Central and the Yankees than the model is, creating opportunities to invest in other teams in the division. The division odds appear to have the best value right now, but there are plenty of bets that could provide much more surplus value in the future. We will keep you updated with consistent updates as those opportunities come up!

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