The Tampa Bay Rays have dominated this baseball season from the opening weeks, when they became the fourth team in MLB history to start 13-0, joining the 1884 St. Louis Maroons, 1982 Atlanta Braves and 1987 Milwaukee Brewers. The Rays have won a lot more since then, and they’re on pace for 120 victories, a total that would eclipse the record of 116 shared by the 2001 Seattle Mariners and 1906 Chicago Cubs.
Not only are the Rays winning, they’re dominating their opponents. As of Thursday morning, Tampa Bay had scored 122 more runs than it had allowed, the highest run differential in baseball and 35 runs better than the second-place Texas Rangers. After finishing 25th out of 30 teams in home runs last season, the Rays have hit a league-leading 86 homers. Only the 2000 St. Louis Cardinals and 1999 Mariners had more during their first 43 games of the season. The Rays are on pace to easily break the single-season record of 307, set by the 2019 Minnesota Twins.
In almost any other year, that kind of performance would be enough to run away with a division title, but this year’s American League East is far too strong for that. In fact, it seems poised to be one of the strongest divisions in recent years.
The four other teams in the division — the Baltimore Orioles, Toronto Blue Jays, New York Yankees and Boston Red Sox — have winning records, the only division able to pull off that feat this season. (As of Thursday morning, the AL West was the only other division with even three teams at or above .500.) The Orioles, who trailed the Rays by 3½ games as of Thursday morning, would be leading every other division. But the raw win-loss records, impressive as they are, actually don’t do the division justice. It is even stronger than it looks on paper.
Since MLB realigned in 2013, moving the Houston Astros to the AL and giving each league 15 teams, the combined win rate for the 2023 AL East is the highest of any division at this approximate point of the season (a combined .620 after each team played 40 games). The division had a plus-207 run differential at the 40-game mark, almost double that of the 2020 NL West (plus-118), the next best division since 2013.
By comparison, the NL Central had the second-highest run differential (plus-18) at the 40-game mark this season. This year’s AL Central had a minus-165 run differential. The largest run differential by a division since the latest realignment was established by the 2021 NL West, whose teams outscored opponents by 443 runs. This year’s AL East is on pace for a run differential of plus-838, which would obliterate that mark.
Run differential helps identify baseball’s best teams, but an even better way is baseruns, a measure of how many runs a team should have scored or allowed given its offensive and defensive performance. The math behind baseruns can be daunting, yet because it removes the effects of sequencing — the order in which outcomes occur — from performance, it gives us a better valuation at the team level.
Here’s a simple illustration of how and why it works. A team draws four walks in a nine-inning game. If those four walks were issued consecutively in an inning, it will create a run. But if those walks were spread out over four innings, they might have no impact on the scoreboard.
We can take it a step further and use the expected statistics for each team to derive baseruns. These expected stats use metrics such as exit velocity and launch angle to determine the likelihood of a hit, further stripping away good or bad luck a team might be experiencing from the inputs into the baseruns formula. For example, the Kansas City Royals are batting .234, but we would have expected an average of .249 based on balls in play, per data from the website TruMedia. So instead of 275 base hits, we can give Kansas City credit for 293 in the formula.
Next, we can adjust each team’s performance via baseruns for strength of schedule, also known as a simple ranking system, showing us how many runs per game above or below average each team should be scoring this season. Then it is a simple exercise to rank the teams to get the best and worst MLB has to offer in 2023. All ratings are as of Monday morning.
The top team in this expected baseruns formula adjusted for opponent, the Rays, should not surprise anyone. Their performance fuels an estimate of 1.5 runs per game better than an average team. The Los Angeles Dodgers (+1.3) are second, followed by another AL East team, the Blue Jays (+1.0). The Red Sox (+0.7, seventh) and Yankees (+0.5, ninth) also rank in the top 10. (The Orioles are considered an average team by this metric and rank 16th.) Still, no other division has more than two squads in the top 10, making the AL East clearly the strongest division in baseball.
But because of baseball’s playoff format, at least one of these teams will miss the postseason, and head-to-head attrition could take a further toll. Oddsmakers aren’t convinced the eventual World Series winner will emerge from the game’s strongest division. The odds for the World Series winner to come from the AL East are between +250 (wager $100 to win $250) and +300, depending on the sportsbook. The NL East is typically the second choice at around +290 odds, while one oddsmaker, Caesars, has the NL East as a slight favorite. Two teams, the Atlanta Braves (+500 at FanDuel) and Los Angeles Dodgers (+500 at FanDuel), are also given shorter odds to win the World Series than the Rays (+650 at FanDuel).
Looked at another way, those odds imply the Braves have a 17 percent chance to win the World Series, while the Dodgers have a 14 percent chance. The Rays, with a 13 percent chance, are tied with the Astros.
correction
A previous version of this article incorrectly said the Oakland A's are in the American League Central. The article has been corrected.