The Japan international has been out of action since October after suffering the problem during United’s 3-2 Champions League win over Braga.
The 23-year-old, who sealed a move to Old Trafford from Borussia Dortmund back in June, has scored two goals in eight appearances for the Red Devils – and Ferguson suggested he could be in his plans for Sunday’s clash against the Premier League champions.
“Shinji Kagawa’s injury has been longer than we thought. He’s much better now and I don’t think he’s far away,” Ferguson said.
“He started running today and he may make the bench [against Manchester City]. Obviously Nani and [Antonio] Valencia are still out and that’s why I played [Wayne] Rooney on wide right.
“I thought it was his best performance of the season. Against Cluj I’m picking a team without any thought of Manchester City. It’s a matter of who needs a game.”
Highly-rated Kagawa scored 29 goals in 71 appearances for Borussia Dortmund before securing a move to England in the summer.