Last year’s Mets wouldn’t have made it to October, but for the good fortune of playing in one of the worst divisions of the Wild Card era. They were 90-72 overall, but 47-29 in the 76 games they played against the Nationals, Marlins, Braves and Phillies. They had a +69 run differential in those 76 games, and a +70 run differential overall. In other words, against the league beyond the NL East, the Mets were a .500 team, with a .500 team’s run differential.

That’s not intended as a poke at the Mets, of course. Indeed, having a strong record against one’s division rivals is not only a good way to win a lot of games (since the unbalanced schedule MLB uses these days includes 19 games against each member of the division), but the surest way to answer the question the regular season now seems meant to answer: Who is the best team in each division? There’s even something to be said for teams who win a high percentage of those games, because the sample size of each season series is so much larger than it is between any given team and an interdivisional opponent, so each series result probably implies something closer to a real expression of relative team quality.

Besides, there’s a team like this just about every year. The 2014 Dodgers were 50-26 against the NL West, and 44-42 against the rest of baseball. Their +101 run differential shrinks to +5 if you remove divisional play. My favorite might be the 2011 Tigers, who finished 50-22 against the AL Central, outscoring those four opponents by 111 runs. In their other 90 games, they went 45-45, and were outscored by 35 runs, but they still ran away with the division.

Now, the 2015 Mets won their division by a cushy seven games. The 2014 Dodgers won theirs by six games, even though the second-place Giants reached the playoffs, too. Those Tigers were the only AL Central team to finish over .500, and clinched the division title two weeks before the end of the season. I don’t think, though, that they were each the runaway best in their divisions. To the contrary, it’s my hypothesis that teams like these tend to pop up out of closely clustered divisions, or at least ones with two or three legitimate contenders for the crown. It’s an accumulation effect, I think, where teams of roughly equal quality beat up on one another, and the one with just a little separation over all the others ends up rising farther above the pack than true talent would suggest. The 2015 Mets had the NL’s seventh-best third-order win percentage. The Nationals were fourth; the Marlins were ninth. New York won the division by a margin that didn’t reflect their actual ability, because of the dynamics of the division itself.

This is a flimsy little hypothesis of mine, and perhaps an easily trounced one. I bring it up, though, because the American League offers three fairly muddled divisions this season, and I find myself casting about for the team who could create a matchup advantage within their division (or merely minimize their disadvantage), allowing them to break away from their particular pack. I found one team who faces, if nothing else, a particularly extreme matchup situation, and who might be able to exploit it.

The Red Sox have had a rocky spring training, in the only way in which I believe it’s possible to do so: They’ve had to deal with injuries in their starting rotation. If you were open-minded enough to consider, coming into camp, that the final two spots in the starting rotation were available to the winners of a competition between Eduardo Rodriguez, Brian Johnson, Joe Kelly, Henry Owens, Roenis Elias, and Steven Wright, there’s bad news: Rodriguez and Johnson, by far PECOTA’s favorites of the group, are both dealing with leg injuries that are likely to keep them sidelined for at least the first few weeks of the season. Thus, Kelly looks like an ironclad lock for one spot in the rotation, and although our depth chart page for the Red Sox shows Johnson, Owens, and Elias all getting more starts than the 31-year-old, knuckleballing Wright, Roster Resource pegs Wright as the likely winner of the fifth job.

Now, PECOTA does like Wright better than all of the other healthy hurlers, including Kelly. Still, it seems like a great loss, this prospect of the Red Sox, loaded with so many promising young left-handers, instead filling out their post-David Price rotation with uninspiring veteran right-handers. It’s not sexy, and worse, it feels suboptimal, like the team is choosing the easy names over the risky ones who might provide the upside to get them out of their two-year run-prevention funk. As I look over their schedule, though, I have to admit: There might not be a worse team in recent memory on which to try to break in young southpaw starters.

You already know about the Blue Jays—the juggernaut offense, or at least that’s what they were last year, loaded with right-hitting lefty mashers. Toronto batters battered lefties to the tune of a .278/.354/.463 aggregate line last season, and although their core isn’t the youngest or healthiest in the game, there’s not much reason to expect they’ll be less lethal this year. Fifteen years ago, that would be a fairly minor consideration, but under the parameters of a heavily unbalanced schedule, it’s a bit larger one: The Sox have to try to keep that offense in check 19 times this season.

Counterintuitively, the Yankees are a little bit like the Jays. You wouldn’t jump to that conclusion, looking down a lineup that features lefties Jacoby Ellsbury, Brett Gardner, and Brian McCann, plus switch-hitters Chase Headley and Mark Teixeira, but strangely, Gardner and McCann have been better against lefties over the last two years (a Yankee Stadium effect? I suspect so, but the Red Sox will still play in Yankee Stadium this season, so even if that be the case, it remains relevant), and Ellsbury, Headley, and Teixeira have virtually no split. New acquisitions Starlin Castro and Aaron Hicks are both better against lefties. Alex Rodriguez is much, much better against lefties. It’s a narrower margin, but the Yankees represent another 19 games on the schedule in which the Sox might prefer to trot out a right-handed pitcher. Last year, it was also true of the Rays, though they balanced their offense nicely this winter (Hank Conger, Logan Morrison, Brad Miller and Corey Dickerson outweighing Steve Pearce).

On top of all that, remember that the Sox must play half their schedule at Fenway Park. Park factors suggest Fenway is actually friendlier to left-handed hitters than to right-handed ones, and given that most hitters hit most of their flyballs the other way, that’s believable. Still, the dimensions, the quirks, the Monster, make the park feel like home for right-handed batters, and it’s good to make them feel less comfortable there when possible.

The Twins, White Sox, Tigers, Astros, and Angels all have distinctly right-leaning lineups. The Mariners and Rangers do lean left, and the margins here are all small—small enough to be overcome by real gaps in talent, rather than negligible ones. Since the gap in quality between most of Boston’s options is razor-thin, though, they might be well served to keep using their slightly less impressive right-handers as rotation filler. At the very least, they ought to proactively swap their young lefties into the rotation when they’re facing teams outside the division, where the matchups work better for them.

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I suppose this is the glass half full look at things. When I look at the rotation after Price and the 1B / 3B situation (what's the record for errors in a season?) I'm more of a glass half empty guy.