The Red Sox can’t worry about handedness when picking their playoff rotation

The Red Sox have had a great month of September so far, and that’s been needed considering how well the rest of the American League contenders are playing. That, specifically, means the Yankees, who have been lights out this month as well yet can’t seem to gain any ground in the American League East. Obviously, the Red Sox still have some work to do to clinch the division and guarantee themselves something beyond a one-game playoff stint, but they are undoubtedly in the driver’s seat. With that being the case, with a week remaining in the year it’s time for them to start looking forward to who will be starting in the postseason and setting up their rotation accordingly. At this point, it seems fairly clear who the top four starters are, though there maybe is some debate between Rick Porcello and Doug Fister. Either way, the two righties are fighting for the top spot. However, despite the names being mostly clear, the order in which they should appear is becoming something of a divisive issue.

The school of thought that believes either Porcello or Fister should appear in Game Three is pretty simple. Given that both Chris Sale and Drew Pomeranz — the unquestionable top two starters in this rotation — are both lefties, some believe the Red Sox should start a righty in Game Three. This is becoming more and more of a prominent thought as the likelihood of Boston matching up with Houston in Game One increases, given that the Astros have a lineup that boasts plenty of right-handed prowess. Despite all that, the Red Sox can’t be concerned with the platoon advantage in this case. They have to go with Eduardo Rodriguez as their third starter.

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The main reason the Red Sox should be committing to the young lefty as their starter behind Sale and Pomeranz is fairly straight-forward: He’s their third best pitcher. This isn’t mind-blowing analysis by any stretch, of course, but the easiest way to form your playoff rotation is to throw out your best pitchers and go from there. Rodriguez has established himself as the third-best pitcher. Obviously, that hasn’t always been abundantly clear as the southpaw certainly had a rough patch in the middle of the year. Of course, that coincided with his return from a knee injury and it now appears obvious that he was still feeling some effects — whether they be physical or mental — from his ailing knee. Prior to the injury, Rodriguez was lights out and looked to be making the leap to an upper-echelon mid-rotation arm in this league. He’s also seemed to recover from his knee injury of late, and he’s getting back to his pre-injury self. Over his last four starts he’s pitched to a 1.78 ERA over 25 ¹⁄₃ innings of work with 30 strikeouts and eight walks while holding opponents to a .549 OPS. This is very clearly better than Rick Porcello — who has taken one step forward and three steps back all year — and Doug Fister — who has taken a major step back after a shockingly solid run.

I don’t think it’s much of a mystery to most that Rodriguez is the third-best starter on this team, of course. The issue, as stated above, is handedness. Well, the numbers show that even in this respect Rodriguez is the better option than Porcello, at least. Over the course of this season, so even including Rodriguez’ down period after returning from injury, the lefty has allowed righties to hit .220/.291/.401 for a wOBA of .297. (For reference, wOBA is on the same scale as on-base percentage, so .297 is an outstanding mark.) Meanwhile, Porcello has allowed a slash-line of .285/.322/.467 for a .334 wOBA. That is not as good! Rodriguez has also been much more impressive in K%-BB%, the best measure of controlling the strike zone in this writer’s opinion. He has a K-rate 17 percentage points higher than his walk-rate compared to Porcello’s being just 15 percentage points higher. All of this to say is that, despite the handedness, Rodriguez has been better than Porcello this year even if you’re only talking about facing right-handed hitters.

Predicting the Red Sox playoff roster

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It’s worth noting that Fister has better numbers against righties this year than Rodriguez but even after his step forward on Sunday it’s hard to see him having the inside track over Porcello. Granted, that could all change if Porcello struggles again his last time out, but even if Fister pulls ahead it’s hard to have more confidence in him than Rodriguez.

The focus for the Red Sox right now is to wrap up the division, something that only an epic collapse over the final week of the season would prevent. Beyond that, they need to figure out the best way to advance beyond the ALDS. If they do end up facing the Astros, there may be some temptation to get too cute and base the rotation around matchups. That would be a terrible mistake for this team to make. The easy and correct strategy are the same in this case: Simply start your best pitchers and go from there. For the Red Sox, that means Eduardo Rodriguez takes the ball after Chris Sale and Drew Pomeranz despite all three of them being southpaws.