Pahlsson, acquired from Anaheim at the trade deadline, will likely make his debut for the Blackhawks on Wednesday against Columbus. He had been sidelined since February 1 with mononucleosis.
The 31-year-old native of Sweden has five goals and 10 assists in 52 games this season. He was the leading faceoff man for the Ducks, winning 54 percent of his draws.
Pahlsson, set to become an unrestricted free agent at the end of the season, has 52 goals and 91 assists for 143 points in 544 NHL games with Boston and Anaheim. He was a member of the Ducks' Stanley Cup championship squad in the spring of 2007.
The Blackhawks also assigned left wing Pascal Pelletier to the club's AHL affiliate in Rockford. He failed to score in seven games with Chicago, but leads Rockford with 27 goals this season.