This may seem odd, but Justin Morneau's health could cost Drew Butera his job as backup catcher. Since he was signed as a free agent, Ryan Doumit's role has been describe as backup catcher and everyday DH. Joe Mauer was expected to DH on most days when Doumit was catching. The likely role of the third catcher was to give one of those two a complete day off, while allowing the other one to DH.
Now there is discussion of Morneau being used extensively, or even exclusively, as a DH. The only way Morneau can DH with both Doumit and Mauer still in the lineup is if one is at first base and the other is behind the plate. If Joe Mauer catches 120+ games, it is doubtful the Twins are comfortable with Doumit playing first base that many times. Doumit's playing time is going to be mostly behind the plate. It also means you can give on of those two a day off by having someone else play first. Enter a variety of options, most notably Chris Parmelee.
In short, with Doumit on the bench, instead of the everyday DH, a third catcher makes a lot less sense. With Parmelee forcing his way on the roster and Morneau's health Butera's job may be disappearing.