Agreed to a four-year extension with RHP Rick Porcello worth $82.5 million. [4/6]

For the second time in the past two months, the Red Sox have extended a pitcher who hadn't thrown a regular-season pitch for them. Unlike Wade Miley, whose three-year pact worth $19.25 million qualifies as chump change, Porcello received a real, live payday. It was always going to be that way, of course, since Porcello was closer to his date with free agency than Miley. But does that make this extension a good idea?

You can understand why Ben Cherington thinks so. Porcello won't turn 27 until he's bored of his Christmas presents, yet he's already surpassed the 1,000-inning mark. He's shown stellar control over those frames, consistently notching solid-to-good strikeout-to-walk ratios despite being light on strikeouts. Similarly, Porcello has coerced more than 50 percent groundballs in each of his six seasons. Aliens could invade and imprison humanity tomorrow, and Porcello would nonetheless find a way to toss 180-plus league-average innings.

At the same time, there's a legitimate case to make against extending Porcello. His innings count is impressive for his age, but until recently he's always carried the underachiever label. His next all-star appearance or Cy Young vote will be his first, and he went five years between 100 ERA+ seasons. Additionally, Porcello doesn't miss bats—his contact percentage was similar to Kyle Kendrick, Dillon Gee, and Eric Stults—and until last season he'd allowed lefties to post an post an OPS of .800 or better in three consecutive seasons. Oh, and lest we forget about his FIP-ERA discrepancy and BABIP.

Porcello has over the last three seasons one of the highest BABIPs in baseball. Corey Kluber owns the worst mark, but nobody cares because he strikes batters out; Porcello doesn't have that going for him. Porcello didn't have infield defense going for him either, as Marc Normandin noted, which adds to the complexity of the issue at hand. It's no wonder Porcello inspires disagreement: his statistical profile is unusual, and therefore divisive.

If you can see through the metric-induced haze, Porcello looks like a tolerable middle-of-the-rotation starter. However, therein is another polarizing aspect to this deal: nobody is accustomed to mid-rotation arms making $20 million per season, especially not through an extension.

Six other pitchers with more than five seasons of MLS have signed multi-year extensions over the past two years: Phil Hughes, Jorge de la Rosa, Homer Bailey, Clayton Kershaw, Charlie Morton, and Tim Lincecum. Obviously Kershaw is an ace, Lincecum and Hughes are bigger oddballs than Porcello, and neither de la Rosa nor Morton qualify for the same tax bracket. Process of elimination leaves Bailey, who received $23 million more despite comparable numbers:

That sounds like vindication for Cherington, but remember: Bailey's deal is and was a relative outlier and was given based on promise as much as production. Such reasoning doesn't apply here. Porcello, though young, lacks the breakout profile. He could improve by bettering himself versus lefties and thanks to a slicker infield defense, yet the shift from Comerica to Fenway Park is going to eat into some of those gains. Besides, Cherington seems content with what Porcello is: "The Sox believed the contract made sense based on his track record rather than daydreams about what he might become."

So what other explanation is there? One is Cherington paid Porcello more for a shorter term. This strategy recurred throughout Boston's offseason, as both Pablo Sandoval and Hanley Ramirez seemingly took shorter deals for bigger paydays. Yet that explanation feels dubious in Porcello's case, since mid-rotation starters seem to top out at four years. Maybe Porcello's age would have coerced a team into giving him a fifth year, but nobody can say for sure. (Plus this winter's free-agent class could be flush with above-average starters, which might have worked against Porcello if anything.) Another is that Cherington paid up to keep a pitcher he liked in red socks—though again, that's an odd explanation given how the Red Sox seemed to like Jon Lester a lot, too, albeit at a different price point.

It would seem then that there is no silver bullet explanation. For some, that's fine. Cherington signing off on the deal is enough to provide them with peace of mind—well, that, and knowing the Red Sox won't be hamstrung if Porcello fails to develop further. For others, the unanswerable aspects leave them queasy or against this contract. Altogether, there's enough merit on both sides to call this a curious, if ultimately tolerable deal that is sure to inspire debate throughout its duration.

In that sense, this is the perfect contract for Porcello.