Phil Parkinson is eager to add another option at left-back to provide cover and competition for Denver Hume, who impressed last season.
Mitchell is one option being considered but it has emerged Championship side Luton are also keen on the defender.
Parkinson is hoping to make another five signings, following the permanent arrivals of Aiden O’Brien and Bailey Wright with a new left-sided defender, left-back, striker and a goalkeeper all on the shopping list.
Mitchell and former Everton defender Morgan Feeney have both trained with the senior group as Parkinson assesses a possible move. The Daily Mail report Luton are also tracking Mitchell.
Feeney did not turn 21 until February of this year and as such, would be exempt from the salary cap rules.
Speaking last week, Parkinson said: “We tried to get a couple in before Friday but those deals didn't quite get over the line,” he said.
“It was the decisions of the agents and the players on that one and when you're going for players who have Championship interest, it can be difficult.
“We've had to change tack a bit in the last couple of days and reassess what we're going to do.
“I'm still confident we'll have a strong squad but one or two we thought we could get, are not in the marketplace right now.”
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