The Cubs began the year with three catchers on the roster but finished Saturday's game with only Taylor Teagarden — who started 2015 in Triple-A — available.
Veteran backstop Miguel Montero had to be removed from Saturday's 5-1 loss to the White Sox with what the Cubs are calling a jammed left thumb.
Montero will undergo an MRI to determine where the Cubs go from here.
"We're not sure," manager Joe Maddon said. "He's going through the tests right now. I'm not 100 percent sure. We should know more by [Sunday], but I don't know anything right yet."
Montero hurt his thumb while catching a ball from Jon Lester. He tried to hit with the issue in the second inning, but struck out and told Maddon it wasn't feeling so well.
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Maddon said Teagarden will catch Sunday and veteran David Ross — who was on the 7-day disabled list with a concussion — has been cleared medically if Montero is going to miss time.
Kyle Schwarber is still continuing his education at catcher in Triple-A Iowa, but he is currently in Cincinnati to take part in the Futures Game Sunday night.