In trading for David DeJesus, the A's are addressing early something that needed to be acted on this winter: their offense. After all, in 2010 they tied for 23rd in the majors in True Average with the equally feeble Indians, but that overstates the strength of their attack–rating ahead of the Cubs, Pirates, and Astros when you're being spotted the difference between DHs and pitchers at the plate is far from brag-worthy.

Is DeJesus enough of an answer? Presumably, he'll be taking over in left field, which would seem to be an automatic upgrade from the punchless and often purposeless assortment randomly employed last season. If you want to compare his value to the likes of a nice fourth outfielder like Rajai Davis or a ballpark-generated fiction like Conor Jackson shorn from the park that made him seem like he was something, you might think it an automatic upgrade. Unfortunately, it isn't quite that clear-cut. DeJesus produced a career-high .299 TAv last year before he broke down, in his age-30 season. It is the only time DeJesus has had an offensive season significantly above average for a corner outfielder. Career, his True Average is .273, which would rate as thoroughly average in 2010, right there among the Fred Lewis or Bill Hall types, and just a sliver better than… Rajai Davis, who put up a .268 TAv last year.

In some ways, this is Matt Holliday, the sequel. The A's have only acquired a single season's worth of service time, so beyond the hope that DeJesus gives them 400-600 PAs and  the opportunity to either get a draft pick in 2012 or a shot at dealing him in July if they're not relevant in the AL West standings. That might seem a bit dismissive of their chances in 2011, but they had chances in 2009 too, to the point that the A's were pre-season favorites in some segments of the analysis community; indeed, they were pegged by PECOTA to win, which struck me as a bit of a stretch.

As it was with Holliday, one of the features of employing DeJesus is his value on defense. Despite a rough partial season in right field for the Royals last season, you can sort of see the outlines of the argument, at least if he's put back in left, where beyond questions about adaptation, his weak arm becomes less of a source of frustration. Per Plus/Minus and Total Zone and Clay Davenport's FRAA numbers (and Colin Wyers' coming nFRAA numbers), he's above-average and rangy in left; per 140 games under old FRAA2, he'd be worth about 11 runs above the average left fielder. I don't know if I'd state with absolute mathematical confidence that he'll be worth a full win above average over a full season, but I'm comfortable with accepting the proposition that he'll be good if he's out there.

Which is the other issue about DeJesus: How often will he be out there? Not that he's a latter-day Paul Molitor when it comes to his case of the fragiles, but there always seems to be something cutting DeJesus down a peg when he isn't out-and-out disabled. Last year's thumb issue should be a thing of the past, but hamstring and shoulder woes that hampered him early on in his career. An injury-sapped season like 2008 is a good example of what you can hope for if he's restricted to "just" the ticky-tack accretion of day-to-day hurts; he managed what in some ways was his best full-ish season, with a .283 TAv.

If the range of expectations is that the A's get an average producer in an outfield corner at one of the few slots where you can employ bigger boppers, then the problem he presents is that having him basically puts the A's in much the same place they already were: beyond the two exceptions of Jack Cust (above) and Kevin Kouzmanoff (below), they feature an awful lot of mere adequacy across the lineup. Maybe a Ryan Sweeney/Rajai Davis platoon in right field gives them an OBP boost, just as DeJesus should, but the offense remains underpowered, and with DeJesus' addition, it isn't like they became any faster–DeJesus hasn't had a season in the black with EqBRR since 2007.

From the A's perspective, you can understand that, if they were going to deal from their rotation options, you can respect that they dealt from the back end of the unit as well as from the organization. But from the Royals' perspective, you can like what a last year's worth of a well-regarded but basically just OK outfielder brought back. Add in that DeJesus wasn't a great fit as a right fielder, and with the decision to move Alex Gordon to left, there was no other corner for him, and you can understand the motivation, beyond not paying the $6 million DeJesus is due. To give Dayton Moore some props, this wasn't a bad package to get after making a sensible choice to deal DeJesus. Mazzaro's a relatively finished product with upside, in that he should be in the Royals' rotation immediately, and I'd bet on his being the best non-Greinke in the unit. Marks is college lefty with decent velocity who's already reached High-A in his first full season as a pro, and who might stand out, even among the Royals' thicket of arms on the way up. So you can like the move as a matter of depth and upside, of acquiring immediate help and something to dream on.

Mazzaro is heading into his age-24 season, and has the benefit of a good dose of early experience, having already made 35 big-league starts. He managed 11 quality starts in 18 last year, not shabby, and it added up to a .475 SNWP, which would have rated third on the Royals behind Zack Greinke and the ever underloved comebacking Bruce Chen. In some ways, I'd liken Mazzaro to Tommy Hunter, in that they share and age and a 2010 SIERA (4.78), and in that both of them are going to end up relying on touch and defense than pure stuff. However, Mazzaro's stronger strikeout rate and better assortment suggests–but don't scream–to me that he'll have the better future. As you could say about a lot of guys, if he pushes his strikeout rate up a sliver, and lowers his walk rate just so, you'll have a fine mid-rotation starter. If he doesn't, he'll still be employable, but there's room to grow. He's still working on mastering the lower end of the zone and getting his sinker to generate the sort of ground-ball rates that propelled him through the minors, but he improved in that regard last season, and at his age, the future isn't gloomy. Mazzaro doesn't have a huge platoon issue to overcome, but he could work on holding runners.

Marks came along well last season. The lanky lefty was a third-round pick out of Louisville in 2009, and spent much of the season at Kane County before getting a last-month promotion to the Cal League. His fastball sits in the 90-92 range, slightly above average for a lefty, but he also has good command of his breaking stuff. Striking out 136 batters against 49 walks across 129 1/3 IP makes for something more than just a throw-in, but if his big platoon split persists, he might "only" end up becoming a good lefty reliever. To that point, it's worth noting that he tended to fade after the third inning in the Midwest League, surrendering 43 runs in his 49 2/3 IP after the first three frames, but to be fair, he was just 22 years old, and he improved as spring turned to summer.

In summary, it isn't very sexy to say that this is a trade that should help both teams, but there it is. The Royals acquired what should be the better long-term value, but they've acquired other people's well-regarded second-tier pitching prospects before–why, Mr. Davies, you are still here–and have wound up disappointed. If A's fans are frustrated that all they've got to show for dealing from their pitching depth is a single season of DeJesus, it's worth remembering that Mazzaro was the least of their rotation assets, and if he was the guy to move, realistically, what did you expect them to get? Given the quality of their rotation, I'd compare this decision to the Mets' choice to deal Walt Terrell after 1984–they knew they could deal from depth, and they knew they needed offensive help. Except that DeJesus isn't going to be Howard Johnson, of course, and whether he'll provide enough value to tip the A's from admirable also-ran to genuine threat to the Rangers in a single season probably depends more on what Texas does from here on out than anything the A's do over the rest of the winter.