Celtics president Danny Ainge said Mickael Pietrus should be ready for game action by the middle of January after July knee surgery.

“It feels great [to be in Boston],’’ Pietrus said. “Since I have been in the NBA, my goal has always been to win a championship, and I have a chance to win one so I’m going to give it everything I’ve got with my new teammates. So hopefully at the end of the year, we get what we want.’’

Pietrus injured his right knee in March while playing for the Phoenix Suns. The Suns were close to trading him to the Raptors earlier this month, but Toronto called off the deal when Pietrus’s knee did not test at full strength.