Fleck started his career with Rangers, making 41 first-team appearances before moving England, firstly with Coventry, then United, who he helped rise from League One to the Premier League inside three seasons and earned five Scotland caps in the process.
The 31-year-old, now back plying his trade in the Championship after United's relegation in 2021, has struggled with injury this season after suffering a broken leg in August. He returned in October after two months out, but went off with a knock in a 1-0 home to Rotherham United on November 8 and has not featured since.
Injury issues aside, former Rangers striker Kris Boyd reckons that his former Ibrox team-mate should be a transfer target for the Govan club as manager Michael Beale looks to overhaul his squad following his recent appointment.
"I think Michael Beale has spoken about it that the central midfield area is one he wants to strengthen,” Boyd told Sky Sports. “He’s lost Stevie Davis and it’s not ideal but I wouldn’t be rushing in and just grabbing players for the sake of it, especially in January.
“Moving forward it’s important Rangers do their recruitment properly. The two windows are huge. If there are deals to be done then Michael Beale will want to get them done in January but I think the summer is the most important because there is a massive overhaul of the squad needed.
“There are players out of contract and I think the obvious one for me would be John Fleck at Sheffield United. John has been at Rangers before, he knows it and has been brought up on it. He is a different player from the one that left Rangers, but people like that would be on my radar.”