It's easy, if you've already given up on Carl Crawford ever being a useful piece with the Boston Red Sox, to dismiss his return as more problem than it's worth. But just because he might never earn the total value of his contract after a replacement-level debut campaign and a mostly-missed follow-up doesn't mean that the individual seasons, from here on out, are automatically busts or wastes of money. Given his past -- one that extends to before he ever donned a Red Sox uniform, despite what some coverage of him over the last year seems to believe -- there's reason to think a more productive Carl Crawford is on the way to Fenway.
It also helps that he's coming back right when Daniel Nava, on a descent back to Earth that began with July, seems very close to finally touching ground again. It's not that Nava has been bad for the Red Sox in 2012 -- his presence has been a boon, an unexpected godsend, even, as he's hit .265/.384/.426 with a 116 OPS+ in 55 games and 220 plate appearances, about 55 and 220 more than anyone believed he would see in Boston in 2012. It's that he's scuffled a bit as of late, and while he's certainly better than the 512 OPS he's put up in July, he's likely also not truly the outfielder who posted an 896 OPS (and .358 batting average on balls in play) in his first two months back in the bigs. The answer, as it so often does, lies in between the extremes.
Nava is a useful piece, for sure, as a switch-hitter who has undeniably improved defensively in the past two years. He's likely limited to left field, but with plate discipline that's unrivaled on this iteration of the Red Sox, without the negatives afield that plagued him in 2010, and with a bit more pop than he had during his last time in the majors, he's a positive contributor as a bench outfielder on a contending club. These are all reasons why the Red Sox were able to designate Darnell McDonald for assignment, and it's why, if the Sox so choose, they can deal one of the other outfielders on the roster in the coming weeks in order to clear 40-man space.
What Nava isn't, though, is a realistic replacement for Crawford. And this isn't because of Crawford's contract, either. It's because, in the three years before he came to Boston, Crawford posted a 115 OPS+ and averaged 4.5 wins above replacement per season. Nava, who is just one year younger than Crawford, hasn't had the opportunity for that kind of success, but is also highly unlikely to produce those sorts of numbers consistently, either -- he didn't just miss an opportunity because he woke up late on the day they were handing out starting outfield gigs. You don't have to dislike Nava to believe that -- as said, he's a very useful piece, an outfielder one hopes the Red Sox hold onto not just because of team control, but because of that utility, his potential production, and the fact he can do just what he's done over the past two-plus months. The fact his path to the majors was interrupted by one stumbling block after another makes him likable as can be, the easiest player on the club to root for, but he can be a big-league ballplayer with a big-league paycheck without starting in left 150 times a year, too.
Conversely, you don't have to believe Crawford's contract is perfect in order to think that he's capable of producing. He's likely overpaid. What of it? Being overpaid doesn't mean that anything produced is a waste, and if the Red Sox have plenty of one thing at any time, it's money, even in this age where being under the luxury-tax threshold might be more appealing than crossing it. The return on investment might be ugly, and you can categorize the money above-and-beyond what he's able to produce as "waste", but if Crawford can play, and well, as he did in his time prior to 2011, from here on out, the standings --and Red Sox -- are unlikely to care much about that.
This isn't to say you should dismiss any questions you have of Crawford. He still needs to show that he's both healthy and able to produce, as his 2011 was ugly, and even the more positive parts had flaws. But, his past merits a second chance, as far as your patience as a fan is concerned, and he's coming at a time in which the Red Sox could use his particular amalgam of skills, as they see just which direction their season is heading in these last few weeks of July.