Prior to tonight's game against the Angels, right fielder Shin-Soo Choo injured his calf while running in the outfield.
Per T.R. Sullivan, it's an injury the Rangers are concerned may not be minor in nature. Minutes later, Billy Casey of Shutdown Inning reported that Nomar Mazara was pulled from a game at Triple-A Round Rock. Naturally, the speculation is that Mazara will be getting the call-up.
While a move to get Mazara onto the 25-man roster would need to be made -- likely placing Choo on the DL if it's serious enough to merit this kind of move -- we'll need to wait and see if the move ends up happening first. It's entirely possible that the Rangers are simply hedging their bets, will re-evaluate Choo tonight and tomorrow morning, and see where things stand from there.
Then again, if they already feel the nature of the injury will have Choo missing significant time, a move could be a mere formality. More as details are available.