Oates has been in superb form recently and boss Nigel Clough said: “He felt his thigh I think. He was springing in this corner and felt it.
“We’re not quite sure yet, but hopefully it’s not too serious.”
Stags were also missing left back Stephen McLaughlin and Clough added: “He got a bang on the head in midweek and we don’t take chances on anything like that.
“We missed him today. We missed his natural left foot and his quality.
“Lucas (Akins) filled in there and did what he could, but he felt a little bit tired after the other night as well. That was his first start since early December.”
The draw extended Stags' unbeaten league run to 11 games without defeat and Clough said: “I thought that was the best part of our game today, the defending.
“I thought Oli Hawkins especially was impressive, every ball into our box we dealt with.
“Despite the pressure they’ve put us under, I don’t think Nathan Bishop has had a shot to save.”
“In the end, we’re very pleased with a point.
“We were frustrated with the first half because we dominated the game and didn’t do enough to go and get a goal in that time.
“The game never lasts that way or stays the same after half-time.
“They’ve come out for the second-half and all of a sudden put us under pressure far more than the first 45 minutes and it was a different game.
“That’s why we were a little bit upset at half-time that we hadn’t done more in the first half.
“This is the next stage now for the players to sense when there’s a game there for the taking, for the winning.
“Don’t give a team the opportunity to come back into it.
“If you get a goal or two then they can have their spell with our two goal lead and we’ll defend accordingly.
He added: : “It was difficult conditions again. The wind is blowing around which isn’t helping, but I thought our attacking play was poor in and around the penalty area.
“Even the likes of Jamie Murphy looked a yard off it today.
“Oatesy, I think if he’s fresh, he goes past people and goes clear a couple of times today. We weren’t quite at it.
“After the effort that’s gone in on Tuesday, we made a couple of changes.
“It just shows the need that when we get to March and April and we get to Saturday, Tuesday, Saturday — we’ll change four or five.”