The Pirates have placed catcher Ryan Doumit on the disabled list with a concussion, and will replace him on the roster with the recently-demoted Jason Jaramillo. Jaramillo will split time with the Erik Kratz until Doumit returns.
General manager Neal Huntington described the decision to place Doumit on the DL as an aggressive one, given that Doumit wouldn't have needed a full two weeks of rest to recover. However, the best case scenario is that Doumit could have returned late next week, and the Pirates couldn't afford to go without a backup catcher for that long...
Then there's the concern of Doumit's concussion history, which has some length. He missed three games in mid-June with concussion-like symptoms and has suffered a concussion in three of his last five seasons.
Doumit collided with Rickie Weeks last night and felt nauseous afterward; now he has a "mild concussion." He also missed a game a few days ago after being struck in the mask with a foul ball. Given all the hits he's taken recently and his history with concussions, keeping him off the field for a while seems like a good decision. Even though it might be relatively safe for him to play in less than the two weeks he'll have to spend on the DL, placing him there allows the Pirates to have a little more roster flexibility.
With Doumit out, it remains to be seen how playing time will be divided between Jaramillo and Kratz. Kratz, a righty, will presumably start against most lefties.