#2 Lack of form
When he joined Manchester United, Alexis Sanchez had been on fire for Arsenal. In the 2016/17 season, the Chilean had scored 24 goals and registered 10 assists from 38 appearances in the Premier League.
He had also scored 3 goals and recorded three assists from eight games in the UEFA Champions League. Just before joining United, in the first half of the 2017/18 season, Sanchez had scored seven goals and registered three assists from 19 games.
The Chilean was expected to hit a higher gear after the move to United, much like his predecessor Robin van Persie. However, Sanchez failed to have any impact at Old Trafford and cut a sorry figure on the pitch in the colours of United.
The Chilean scored just three goals in the Premier League since his transfer and has looked an entirely different player. His dribbling has hardly been effective and his performance has waned with each passing game. Having him around for Solskjaer's rebuilding exercise this season, as such, makes very little sense.
#1 Youth promotion
Ole Gunnar Solskjaer's attempting to rebuild Manchester United with a backbone of young players who can reign supreme at the club for years.
The Norwegian has already managed to field a very youthful side this season and youth promotion was also one of the reasons why Romelu Lukaku wasn't replaced at United.
Similarly, Sanchez's departure provides an opportunity for someone from the youth ranks to step up. Manchester United currently have Anthony Martial, Marcus Rashford and Mason Greenwood as their main strikers, so the Chilean's departure does have a degree of risk associated with it.
However, it is a risk worth taking, as United can introduce another teenager from the youth ranks into the squad, with the hunger and desire that would bond well with Solskjaer's rebuilding.
The trust Manchester United bestowed on Alexis Sanchez was never repaid. As such, putting their faith on youngsters might just work for the Red Devils now.