Last summer, catchers Geovany Soto and George Kottaras were traded in July, while Kurt Suzuki and Kelly Shoppach were dealt in August. This year's market for backstops appears similarly uninspiring. The Tigers and Yankees are a couple of teams that could be in the market.
Starters
John Buck (Mets), Ryan Doumit (Twins)
Buck, 32, has hit .176/.263/.243 in 152 plate appearances since May 5th. Anthony Recker serves as Buck's backup. Mets fans await the big league debut of Travis D'Arnaud, the key piece in the R.A. Dickey trade over the offseason, as D'Arnaud recovers from a broken bone in his foot. At last check, D'Arnaud was cleared to run in water. If D'Arnaud needs more than a month, Buck could still be moved in August given his $6MM salary and lackluster hitting. The Mets' goal should be modest with a Buck trade; he can back up somewhere and they can receive some salary relief.
Doumit, a switch-hitter, still has decent pop. He's more of a catcher/designated hitter/occasional first baseman/corner outfielder. The Twins gave him a two-year, $7MM extension in June of last year, so it's possible they'd prefer to retain him for 2014.
Backups
Dioner Navarro (Cubs), Hank Conger (Angels), Carlos Corporan (Astros), Jeff Mathis (Marlins), John Baker (Dodgers)
Navarro should be particularly available, since he's a free agent after the season. He has a .468 SLG in very limited duty the last couple of years. Conger and Corporan have also shown a bit with the bat this year as backups; their availability is uncertain. Mathis made his season debut in mid-May after a broken collarbone, and has only 57 plate appearances on the season. He's under contract for $1.5MM in 2014, with a club option for '15.
Other Possibilities
Should the Phillies adopt a more certain seller stance, impending free agent Carlos Ruiz should be available. His season began in late April after he tested positive for Adderall, and then he later missed time with a hamstring injury. We've yet to see whether he can be an asset offensively this year. He's earning $5MM. The Brewers' Jonathan Lucroy is signed through 2016, possibly '17, and I imagine they'll keep him. Ditto for the Angels and Chris Iannetta, who is signed through '15. I can picture the White Sox moving Tyler Flowers, though he wouldn't really help a contender.
Biogenesis Effects
The Yankees' Francisco Cervelli is currently recovering from a broken hand; the team has used Austin Romine to back up Chris Stewart in his absence. If Cervelli is suspended for his connection to Biogenesis, the Yankees' desire to add a veteran could increase. There's also Padres starter Yasmani Grandal, who has already served a 50-game suspension for testing positive for testosterone. If MLB manages to slap a 100-game suspension on him, he could be done for the season. The Padres would presumably turn back to Nick Hundley, but could at least look for a backup having cut Baker earlier this month. They did subsequently add Chris Robinson to their Triple-A club, for which Rene Rivera is playing well.