Sanchez completed a season-long loan move to Inter Milan on Thursday, signalling the end of a torrid 18-month spell at Old Trafford.
The Chilean left United having scored just three goals since a switch from Arsenal and left on the periphery of Solskjaer’s squad.
Manchester United manager Ole Gunnar Solskjaer arrives at the club’s Carrington training base on Friday morning ahead of their visit to Southampton
The United manager admitted that Alexis Sanchez has to leave the club to save his career
Poor form and injury problems had made Sanchez a bit-part player at United under Solskjaer
‘Alexis needed to go,’ Solskjaer said. ‘We know it’s not really worked out for him. It’s for him to restart, playing regularly and scoring goals.
‘That’ll only benefit everyone. For us, we’ll watch him every weekend with Romelu (Lukaku) playing together. He will come good for them.
‘We had a decision to make. I’m trusting Anthony (Martial), Marcus (Rashford) and Mason (Greenwood) to be our centre forwards.’
Greenwood is pushing for a possible starting spot against Southampton on Saturday lunchtime as Martial struggles with a thigh injury.
Inter unveil Alexis as their latest signing after he completed his loan switch to the San Siro
Solskjaer is prepared to trust 17-year-old striker Mason Greenwood to lead United’s attack
The 17-year-old has come off the bench in each of United’s first three games this season.
‘Mason is not used to playing as little as he is at the moment,’ Solskjaer added. ‘He’s coming on for half an hour here and there.
‘It’s a learning curve for him. He won’t be expected to play five games on the bounce, he’s cover for Anthony and Marcus.’