Why do the Red Sox need Jake Peavy?

It's reasonable to wonder why the Boston Red Sox would trade one of the game's more promising young shortstops for a starting pitcher who hasn't managed even a dozen wins in a season since 2008.

Well, you may either applaud or castigate the modern postseason at this point. Because without it, it's quite possible that the Red Sox wouldn't have traded José Iglesias to the Tigers for Jake Peavy (yes, with a bunch of other players involved in the three-team deal). The Red Sox have played exceptionally well this season. In the toughest league's toughest division, they've compiled the second-best record in the American League and the second-best run differential. They do have some legitimate concerns, but they're a great bet for the postseason, whether as division or wild-card winners.

Ah, but there's the rub. Wild-card winners ... wild-card winners draw the wonderful honor of opening the postseason in a one-game, winner-take-all first round. Joe Sheehan calls it a coin-flip game and he hates it, because it's not fair. I see his point. But a) it's not necessarily a coin flip, because an appreciably better wild-card team should be able to set up its pitching rotation for the one-gamer, and b) fair or not, it does make for compelling television.

More to the point, as a fan I want to see the Red Sox really giving a damn at the trading deadline, and really doing their best down the stretch to ace out the Tampa Bay Rays.

I'm not completely convinced that Peavy gets the Red Sox there. After all, from 2009 through 2012 he averaged just 21 starts per season, and he's made only 13 this season. He has pitched well when he's pitched, of course, with the only blot on his record those 14 home runs allowed. Which is a problem that probably will take care of itself.

Will the Red Sox miss Iglesias? Probably not much. They've got Stephen Drew to play shortstop this season, and hot prospect Xander Bogaerts to play shortstop next season. And for third base this season, their options include Bogaerts and Will Middlebrooks down in Class AAA.

Of course, the odd thing is that Iglesias was hitting like a third baseman while playing third base, while eventually he'll probably hit like a shortstop while playing third, and Bogaerts hits like a third baseman and probably belongs there in the long run, even though he's always been a shortstop.

Got all that? I'll bet the Red Sox do. Which isn't to say everything's going to work out wonderfully. Peavy has to stay reasonably healthy, both this year and -- if he's not the key in a World Series-winning season -- next year too, as he's under contract for a fair amount of money.

Meanwhile, the White Sox needed prospects -- which they got, in the form of Avisail Garcia from the Tigers and some lesser lights from the Red Sox -- and the Tigers apparently will soon be needing a shortstop. And in Iglesias, they've probably got one for a while. Hey, maybe this is one of those win-win-win situations.

Probably not. Right now, though, everything looks pretty good to me.