The Red Sox handed the Braves their 16th loss in 19 games and moved into a first place tie with the Yankees, defeating Atlanta 5-3 at Turner Field.
The Sox and Bombers improbably share the AL East division lead with 38-28 records. Why improbable? In 66 games, the Red Sox have scored 346 runs and allowed 328, while the New Yorkers have scored 386 and allowed 318. Applying baseball’s Pythagorean Theorem to winning percentage (runs scored squared/(runs scored squared + runs allowed squared) the Red Sox should have a winning percentage of about .527 and have won 35 games while the Yankees should have a winning percentage of about .596 and have won 39 games, in other words a four game lead. Toronto, leading the league in OPS and second in runs, has scored 375 runs and allowed 338, and more notably trails by 2 games.
New York is first in runs scored (despite missing Sheffield and Matsui for much of the year) and second in OPS, while the Red Sox are sixth in both runs scored and OPS. The Yankees are fourth in runs allowed, the Red Sox sixth, although the Red Sox are fourth in K/BB ratio the Yankees tenth, which may have more predictive value going forward.
So what’s the explanation? Winning percentage in one run games, which is often more luck than skill (as analyzed by Bill James), shows the Red Sox have won 10 and lost 6 and the Yankees are 10-10, accounting for exactly the four game difference from expected results by raw offensive and defensive figures. Obviously the success of Jonathan Papelbon, whose 22 saves leads the majors helps.
You can argue that the Red Sox improved defense could play a role, or argue that the Sox playing ten less home than road games also has contributed to their relative underperformance.
Our desire to simplify the complex notwithstanding, I’d say the Red Sox are fortunate sons to be clinging to a tie at this point in the season, relative to the purest measures of offense and defense, run differential.