Over the past few seasons, center fielders Michael Bourn, Colby Rasmus, Jordan Schafer and Scott Podsednik have exchanged hands via trade, and others capable of playing center field have been included in deals as well (e.g. Shane Victorino). Trades for center fielders aren't as plentiful as trades for corner outfielders, simply because good center fielders are hard to come by and thus hard to acquire.
Here's a look at some of the names who could be on the move as we approach the July 31 non-waiver trade deadline...
Regular Center Fielders
The Marlins don't want to trade Ruggiano, but he has an outstanding glove in center field to go along with a nice blend of power and speed. He strikes out a fair amount and doesn't have tremendous patience, but a .249 BABIP has deflated his overall batting line to .218/.288/.397 this season. He's under team control through 2016 and isn't yet arbitration-eligible, so the asking price will be high.
De Aza grades out as a poor defender in center according to advanced metrics, but he's spent the past two seasons as Chicago's primary center fielder and hit well in the process (.274/.339/.413). De Aza will be arbitration-eligible for the second time this offseason after making $2.08MM in 2013, and the White Sox are open to dealing anyone other than Chris Sale and Paul Konerko.
Gutierrez, predictably, has missed a signifcant portion of the season and is on the shelf without a clear timetable for his return. The impending free agent hasn't played in more than 100 games since 2010 and could be moved in August if he can get healthy.
Part-Time Center Fielders
Injuries have pressed Ethier into center field duties this season, and the team may prefer to hang onto him given its recent surge in the standings. However, the emergence of Yasiel Puig along with the presence of Matt Kemp (if healthy) and Carl Crawford could allow the Dodgers to try to shed Ethier's contract. He's just one year into a five-year, $85MM contract but has hit a mere .274/.348/.409 over his past 162 games. That's hardly $17MM production, and there's been plenty of speculation regarding his situation already.
Denorfia and Davis don't play center regularly, but each has significant Major League experience at the position. Both are speedy right-handed hitters who hit left-handed pitching far better than right-handed pitching, so they could serve as a nice bench or platoon component to a contender. Davis is a free agent at season's end, while Denorfia is controlled through 2014.
There's no timetable for DeJesus' return from injury, but he's punished right-handed pitching this season in a return to center field action. He's already played more innings in center field this season than he has since 2008, however, so interested teams could look at him as more of a corner outfield option when healthy. DeJesus has a cheap club option for 2014, so he's more than just a rental.
Wise and Sweeney are both on the disabled list, though Sweeney figures to return at or shortly after the trade deadline. As such, he could be moved in an August trade due to the fact that he's a pending free agent. Wise was recently sent on a rehab assignment and should be healthy before the deadline, but he hasn't hit much in 2013. Chavez has been worse at the plate and figures to be a DFA candidate for the Mariners as much as a trade candidate.
Rios hasn't played center field regularly since 2011 due to De Aza's arrival in Chicago, but he has more than 3500 career innings at the position. He's hitting .278/.333/.432 with 11 homers and 19 steals, and a contending team in need of a center field upgrade as well as an offensive boost could see him as a fit. Rios is locked up through 2014 with a club option for 2015, so Sox GM Rick Hahn will ask for a significant haul.
There's no indication that the Blue Jays will be firm sellers, and even if they end up going that route, GM Alex Anthopoulos may prefer to hang onto his center fielder. However, at 11.5 games out of a first and eight games back from a Wild Card spot, a losing streak could push the Jays into that territory, and Rasmus only has one year of team control remaining before free agency. Interested parties would likely pay a healthy price to acquire Rasmus, who is hitting .251/.324/.475 with 16 homers and strong defense in center field (according to UZR and The Fielding Bible).
For more on the 2013 trade market, take a look at Tim Dierkes' examination of the market for catchers, first basemen, shortstops and third basemen as well as my own look at the market for second basemen and corner outfielders.