Manchester United striker Zlatan Ibrahimovic is set to step up his recovery from injury by returning to Carrington full-time at the end of the month, sources have told ESPN FC.

Ibrahimovic has occasionally used the facilities at the club's training base since undergoing a knee operation in the United States in May, and was pictured in the gym with former United striker Andy Cole on Thursday.

The Swede, who turned 36 this week, is expected to be there on a daily basis by the beginning of November to complete his recovery under the supervision of United's medical staff.

Ibrahimovic was released at the end of last season after suffering a knee ligament injury in the Europa League quarterfinal against Anderlecht in April, but signed a new one-year deal at Old Trafford in August.

Jose Mourinho included the striker, who scored 28 goals in 46 games last season, in his squad for the Champions League group stage, which ends with CSKA Moscow's visit to Old Trafford on Dec. 5. However, the manager has insisted the striker is not expected back until the new year.

Zlatan Ibrahimovic scored 28 goals for Manchester United last season. Manchester United/Man Utd via Getty Images

"He will not be ready for the group phase of the Champions League," Mourinho said in August. "I don't think there will be any chance of that.

"I'm not thinking with Zlatan to play any part in the group phase. Hopefully, he can play in the knockout phase but, for that, we need to finish in the top two."

United are top of Group A after wins over Basel and CSKA Moscow. Should they qualify, the knock-out rounds will start with the round of 16 in mid-February.

Marcos Rojo also suffered a knee ligament injury in the same game as Ibrahimovic and the Argentine defender has taken part in training sessions outside with the rest of the squad, but is not yet being considered for the first team.