The forward, who scored six times in the final eight matches of the season, was hurt by a crude challenge from Glen Rea just before the interval and limped through the final seconds of the first half but did not appear for the second.

But Warburton revealed that Clarke can breathe easily as the problem does not appear to be serious.

Warburton said: "For Lyndon to go down – he never goes down and he's as hard as a piece of teak.

"But I don't think the doctor was too concerned and Lyndon was desperate to come back onto the pitch because he thought he was OK.

"The doctor said he wanted to be cautious, and we'll always listen to the medical staff.  So that was more precautionary, I hope.

"He looks OK – and the way he's attacking the food in the dressing room, he looks fantastic.

"He knows he's got a big summer ahead of him, and we need to look after our players."

Rangers' win meant they finished ninth in the Sky Bet Championship and Warburton feels they have made substantial progress during his two years at the helm.

He said: "It was a really pleasing end to the season to get three more points and take us to 68, which is 10 more than last year.  I'm delighted for the players.

"It's not a huge success, because we haven't won anything, but we're only two points off of seventh and the players deserve so much credit for the way they've worked hard and shown character."

Luton manager Nathan Jones felt his side were punished for missing chances in the first half.

"I thought after the first half that we should have been out of sight," he said.

"We had enough opportunities to kill the game. But in the second half we didn't really get going.

"I'm proud of the performance but we didn't show enough quality in moments and that's the level – if you don't take your chances and put teams to bed they will hurt you.

"It's tough to take because we were outstanding in the first half."

Jones also has reason to be encouraged by his team's showing this season.

The Hatters finished 12th, comfortably avoiding a relegation battle despite many tipping them to struggle.

"We're finding our feet at the level and wanted to establish ourselves as a Championship side and we've done that," Jones said.

"We've finished 12th and if we'd been able to win today we'd have finished 10th. We've had a season of fantastic relative success.

"It's been a very productive season to finish where we have, with 62 points, and never where our budget tells us we should be.

"In over half the games we've got a positive result and that's why we're in the position we are and not in a final-day scrap."