Count me extremely happy with this move, especially as the details continue to roll in; it is a good deal for the Cardinals, and a great deal for Mozeliak.
More important, perhaps, than anything else is that the Cardinals have acquired a creditable shortstop—filling their most gaping hole—without using the majority of their payroll or their top few trading chits. The player they traded, Mark Worrell, was one of my favorites, but he was about as far out of the Cardinals' plans as a guy who strikes out 80 people in 58 AAA innings has ever been and had, in a remarkably odd coincidence, that very day talked with Scout.com about how he wanted to be traded.
That's what makes it such a coup for Mozeliak, providing that none of their scarce starting depth is Named Later—not only did he deal from a positional surplus, he did it in such a way that it did not affect La Russa and Duncan's plans at all, even if it should have. It's the successful version of the Anthony Reyes trade, aided by the fact that the Padres are in severe Payroll Slashing Mode.
Greene, meanwhile, seems like as good a candidate as there is to bounce back after a miserable season. His miserable season wasn't borne of injury problems or age or other things that might recur season after season—it was just miserable, the kind of season that is not caused by a broken hand but is ended by one. I have no analytical heft behind this thought but he seems like the kind of player, as a hacker playing in the wrong ballpark, who might be more prone than the average hitter to completely fall apart over the course of a season and eventually get it back.
And it really was unprecedented; he's never been nearly as bad as he was in 2008. I mean, don't get me wrong, he's had some bad qualities in the past—I can't see his OBP going over .320 without a serious breakout season at this point—but the end result has always been an above-average player. From 2003-2006 his defense, per Ultimate Zone Rating, one of the few PBP defensive stats available that far back, was worth an average of 9 runs per 150 games. Combined with his hitting—according to Baseball Prospectus's PMLVr, which measures the number of runs per game that a player would add to a team compared to a league average player at the position, even at his hackiest he was a little better than the average shortstop—Greene was well above average as a shortstop in 2005 and 2006, and outstanding in 2004 and 2007. It's not often that you acquire a shortstop who was outstanding two seasons ago, did not tear his ACL or get busted for steroids in the meantime, and is now 29 for a relief pitcher who was not in your future plans.
That kind of value distribution, with the genuine potential for high reward and the looming concern of a continued breakdown, is admittedly worrisome on some level, but it's exactly what the Cardinals need at the position. Greene, by sheer virtue of his resume up to this point, seems pretty likely to at least match Cesar Izturis's overall value last year; to not do it would mean he's been the victim of a very rare, very vicious early decline phase or a lingering injury that no one has found. It would require him to bounce back on neither side of the ball. But I'll grant that the Cardinals probably could have found a player more likely to match his borderline-average stylings elsewhere on the market.
What they couldn't have found elsewhere, at least without guaranteeing two years to Edgar Renteria or four to Rafael Furcal, is the chance to add serious value to a team that's still only on the edge of contending. Greene, in a contract year, with a history of success, no longer playing at a historically terrible ballpark for his primary skillset, has the chance to give a team that has not added a lot of upside in the offseason a multi-win boost. He's not just treading water—he's a free shot at a serious positional upgrade. If the Cardinals can do that in the rotation and the bullpen like they've done it here I'll be a lot more optimistic about their chances, but this was an excellent start to their offseason and another bullet point on Mozeliak's budding reputation as a trader.