Last July, shortstops were on the move. A legitimate shortstop prospect was traded when Jean Segura went to the Brewers from the Angels in the Zack Greinke deal, and now Segura is an NL All-Star. The Dodgers acquired a player who had been one of the game's best shortstops, getting Hanley Ramirez from the Marlins. Eduardo Escobar went from the White Sox to the Twins as part of the Francisco Liriano trade. The Indians picked up Brent Lillibridge from the Red Sox; he played some short for Cleveland last year. The Braves acquired Paul Janish from the Reds, while current Mets starter Omar Quintanilla was dealt to the Orioles.
This year, contenders such as the Pirates, Yankees, Cardinals, and Reds could seek a shortstop in some capacity, while any number of non-contenders may seek to add to their prospect stash at the position.
Starters
Jimmy Rollins (Phillies), Alexei Ramirez (White Sox)
Much has been written about whether the Phillies, currently 7.5 games back, will be trade deadline sellers. Even if they do go that route, the 34-year-old Rollins has full no-trade protection and is under contract through at least 2014. The Phillies still have Freddy Galvis and did acquire backup John McDonald recently, so they have options if they find a trade partner and Rollins approves. Ultimately I don't think the Phillies could get a lot back for Rollins, so it makes more sense to hang onto the city's longest-tenured athlete.
Ramirez is worth a mention mostly because the White Sox are out of contention. The 31-year-old is an acceptable option at short, hitting .277/.305/.342 with great durability and a reasonable contract that runs through at least 2015. The extended control could put some non-contenders in play for Ramirez, if he's even available. I was surprised to see Ramirez's age; this is not a player in his prime. I think the return would have to be interesting for the Sox to pull the trigger. Ramirez is not a player they need to unload, and naming Gordon Beckham the full-time shortstop requires a leap of faith.
Backups
Omar Quintanilla (Mets), Adam Rosales (Athletics), Ronny Cedeno (Astros), Brendan Ryan (Mariners), Ruben Tejada (Mets), John McDonald (Phillies), Jamey Carroll (Twins)
It's always good to add veteran insurance; a glove man like Ryan could help a contender.
Other Possibilities
With 20-year-old shortstop prospect Javier Baez getting a promotion to the Cubs' Double-A affiliate recently, is there even a sliver of a chance the team would consider trading Starlin Castro? Though Castro was not brought in by the Epstein/Hoyer administration, and he's not the type of hitter they generally prefer, a midseason trade seems highly unlikely. Castro's terrible season would mean selling very low, high-walk shortstops barely exist anyway, and the front office made a major contractual commitment to him just last August.
With no regular spot for him, the Rangers have turned one of the game's best prospects, Jurickson Profar, into a temporary utility man. If they are to trade him, they'd surely require one of the game's best players in return, such as the Marlins' Giancarlo Stanton. There's no indication the Rangers are open to putting Profar in a deal, though.
Eduardo Nunez missed significant time with an oblique injury, but he's now the Yankees' starting shortstop until Derek Jeter's season debut. The team seems unlikely to move Nunez given the uncertainty with Jeter's health.
Biogenesis Effects
A couple of All-Star shortstops have been linked to Biogenesis in the Padres' Everth Cabrera and the Tigers' Jhonny Peralta. Having dropped nine in a row, the Padres' status as a contender is slipping, so they may not need to act if Cabrera is suspended. The Tigers' alternatives include Ramon Santiago, Argenis Diaz, and Danny Worth, so I imagine they'd have to make an acquisition if Peralta is suspended prior to the August 31st waiver trade deadline.
You can also check out our trade market posts for catchers, first basemen, and second basemen.