Manchester United manager Jose Mourinho warned Zlatan Ibrahimovic that he must earn his position in the starting XI after returning to Old Trafford.

Still recovering from a serious knee injury, Ibrahimovic re-signed for United on a one-year deal Thursday.

The 35-year-old striker scored 28 goals in all competitions last season before he suffered knee ligament damage in April.

Ibrahimovic returns to a United side, which now boasts Romelu Lukaku as well as Marcus Rashford and Anthony Martial, and Mourinho said the Swedish veteran will not be an automatic starter when he comes back from injury.

"Zlatan knows me and he knows that I play the players that I think are best for the team," Mourinho said. "I have always done that.

"So if he comes here and he proves he is the best, he plays. If the other ones don't give him a chance to prove that… that is life.

"But I try always to be honest with my players and with my team. Maybe sometimes I don't always do the correct things but I try."

Mourinho, preparing for Saturday's visit of Leicester City in the Premier League, added: "My squad is better for sure. It is one more option. It is one more striker. It is one more experienced player. It is one more player that can play nine or ten, that can play double strikers.

"We have lots of matches to play. If we progress in the Champions League and if we progress in one of the cups, we would be in a position where we couldn't do it with only Lukaku and Rashford, especially if I play both together.

"If I play with both, I would need another striker so probably in January I would be knocking on Ed Woodward's door asking for a striker for the second part of the season.

"Now I don't need to knock on the door. I have one of the best in the world."