Bailly got back into the starting eleven at Everton on Wednesday night and was solid as Manchester United booked their place in the EFL Cup semi-final with a 2-0 win at Goodison Park.
The Ivorian has again struggled with injuries this season and against Everton, it was only his fourth appearance for Manchester United in the ongoing campaign.
McIlroy wants to see the centre-back get a run of games in the starting eleven to be able to prove to Solskjaer that he can remain consistently fit and perform at the top level.
The former Red Devil said on MUTV: “He needs a run, absolutely he needs a run in the team.
“I know [Victor] Lindelof and [Harry] Maguire are Ole’s first picks, but he needs a run and when he gets in he shows the manager I am fit, I am ready and I am going to be consistently knocking on your door to play in this team.
“He needs that.”
Bailly has played just 89 times for Manchester United since arriving in 2016 due to injuries and McIlroy conceded that being in and out of the side has not helped the defender.
But he feels whenever the centre-back has played he has shown the qualities that made Manchester United sign him from Villarreal in 2016.
“It can’t do any good but his problem has been his injuries.
“When he does play and plays well, it shows you why we brought him here.
“He is a class act but he needs to be consistent.”