Ibrahimović still has a lot left in the tank and he has already become an influential figure at Old Trafford in his lone season with the club.
This comes after he suffered a horrific knee injury against Anderlecht in the Europa League last season which saw him suffer serious ligament damage on his right knee. The pair get on well and Mourinho was hugely impressed not only by Ibrahimovic's 28 goals in his first season, but his influence in a dressing room lacking big characters.
This is a move that many had slated as a possibility when the Swedish striker's contract expired during the summer after a bad knee injury called a halt to his impressive debut season in the Premier League.
The former PSG, Inter Milan and Barcelona striker is still undergoing his recovery work at United's AON Training Centre and it's believed that his rehab is going quicker than expected.
Jose Mourinho has explained why Romelu Lukaku is an excellent addition at Manchester United, claiming he's a good player for the squad to play with.
Barcelona: Australian boy, 7, 'missing' after Las Ramblas attack
Julian has not been seen since the attack, while his mother Jom Cadman is believed to still be in hospital after being injured. A woman from California is also desperately hunting for her husband, who is still missing after the attack.
'It was very clear from him that what he did previous year was not enough for him.
Ibrahimovic turns 36 in October.
After successfully having cruciate ligament surgery, Ibrahimovic appears to have made huge progress as he struck the punch bag with a fierce kick using his right leg.
LA Galaxy were understood to be keen to sign the striker in July, but he would prefer to return to United, even though his wage will be significantly lower than it was in the one-year deal he signed with the Red Devils after joining on a free transfer from Paris Saint-Germain in June 2016.