Run differential isn't a perfect yard stick for gauging just how good or bad a team is supposed to be, but in many ways, it's more accurate than actual wins and losses. As it's just mid-June, not enough of the season has gone by to believe today's won-loss records are simply smaller versions of those we'll see in the end-of-season standings. Mid-season run differentials, however, are often just that: an earlier, smaller gauge of where a team is likely to end up.
You're not hearing anything revolutionary when told that teams win when they outscore their opponents. Run differential simply shows the difference between runs scored and runs allowed for each, so, in theory, the clubs with the top run differentials at year's end are oftentimes also the top teams. There can be hiccups along the way, and in either direction, for a variety of reasons: great bullpens helping to win a multitude of close games, lineups inconsistent with their run scoring whose run differential is built from a few blowouts, or just plain luck, good or bad, with runners in scoring position. This types of things are more prominent in June than they will be by September, when more games have been played that tend to even out these trends, and it's easy to spot in today's standings.
Out of MLB's 30 teams, 11 are at least six games off of the pace set by their run differential. 19 of 30 are four games off, and when 16 of 30 teams are within 4-1/2 games of first place -- and 13 of the 24 teams not in first are within four of a Wild Card spot -- that has massive implications for the standings, both now and in the future.
That's because, whether teams deserved to win or lose those contests, they did. Those Ws and Ls are in the books, and no amount of run-differential goodness or badness is going to change that, no karmic retribution is going to come to set things right. Teams just have to hope things are more in their favor going forward, and enough so that their earlier, possibly undeserved scuffles won't cost them in the end. That is, of course, unless the team is benefiting from this unbalance.
The St. Louis Cardinals lead the way in terrible luck, as they sit just one game over .500 and 3-1/2 games out in the NL Central, despite an expected record that says they should be 10 wins better than that. This all despite the loss of Lance Berkman, the underwhelming start to the year of Adam Wainwright, and the various other injuries that have sapped their depth and potency in the first half. Out of all of the contenders, the Cardinals have had it the worst, but they aren't alone.
The Red Sox are six games out of first place in the AL East, and three games out of a Wild Card spot. Their expected record is six wins better than their actual record, thanks to the third-best run differential in the American League, behind only the Yankees and the Rangers. The Red Sox are 0-4 in extra innings games, despite a strong bullpen, and they're 7-8 in one-run games overall. Contrast this to the Orioles, who lead Boston in the standings by three games, and have also won eight more games than their +4 run differential suggests they should have. St. Louis is dealing with a similar situation when it comes to the Pirates, who are also eight games ahead of their expected pace. At least Baltimore has managed to outscore their opponents, whereas Pittsburgh has a -20 in that column.
The Orioles and Pirates aren't the only teams in the contention mix that are well over their heads at the moment, though, as the 36-32 Indians have a run differential of of -31 that says they should be closer to six games under .500, and out of the way of the White Sox, who are +33 yet half-a-game back of the Tribe. The Mets, who are tied for the Wild Card lead in the NL, should be at .500, rather than six games over, but to make that situation fun, the team they are tied with -- the Giants -- have the exact same record, and exact same discrepancy in it. The Mets are +3 on the season, the Giants +2, yet both clubs sit at 38-32.
It's not just competing clubs who are affected by this, though. The Rockies, in the midst of an atrocious 25-42 campaign -- and most of that was with their star Troy Tulowitzki around -- are eight games worse than expected. Lackluster fielding, pitching problems, and the altitude-inflated offense have all contributed to this, but things could be better, even if that wouldn't necessarily make them good. The Cubs, who are in sell mode in their first year under Theo Epstein and Jed Hoyer, are also eight games back of their run-differential pace. Those eight wins wouldn't help them compete, but it would move them from a league-worst 14½ games out to a more palatable 6½.
Just because run differential suggests one thing doesn't mean that a team is guaranteed to move closer to that alternate reality. But it does help to differentiate between teams that are just hanging on in the short-term versus those that are legitimately contending within a given season, and between those who need to add a bat or arm in July against those who simply need more time to get to where they should be. It's something to keep in mind as we approach the season's fourth month, even if it's no guarantee of change.