His first act as a Yankee?
Surgery.
Luckily, it's not a big deal--They wouldn't have signed him if it was. Here's more from George A. King III:
The newly signed catcher has a small meniscus tear in his right knee and will have arthroscopic surgery Monday.
Martin passed his Yankees physical making the deal official Thursday.
"It's a three-week recovery period,” GM Brian Cashman said. “We can take time with this. He will be full-throttle when called upon. We don't want it to become a problem. It's not a serious surgery at all."
CC Sabathia and Jorge Posada, who is moving to DH and being replaced at catcher by Martin, have undergone similar surgeries earlier this offseason.
"As long as he's healthy he will be the everyday catcher," Cashman said of Martin.