Charlie Adam last night revealed he will be unable to contribute to Rangers' Clydesdale Bank Premier League title challenge because of red tape over his registration.

Adam has been on loan to Blackpool since February but their Coca-Cola Championship season ends against Swansea tomorrow. The 23-year-old midfielder hoped it would free him up to return to Ibrox for their remaining league games and the Scottish Cup final.

Adam will return to Scotland days before next weekend's final Old Firm game of the season but has accepted that tomorrow's Blackpool fixture will be the last game he can play this season after looking into his contract situation.

"My contract at Blackpool runs out on June 2," he said. "I had thought that I could go back and play again for Rangers. But the rules are the rules. I think it's because it's two different national associations involved and another international transfer, which means that I can't be registered to play again for Rangers this season. I'm a wee bit disappointed about it, to be honest."

Adam made only nine appearances for Rangers this season before leaving on loan but two of those were Old Firm games. Manager Walter Smith appreciated his discipline and defensive work-rate as a wide midfielder and gave him starts at Parkhead in August and again when Celtic were at Ibrox on December 27.

It was his last appearance before leaving for Blackpool on the final day of the January transfer window.

Since then he has watched from Lancashire as the Old Firm had a 0-0 league draw in February and Celtic beat Rangers in the Co-operative Insurance Cup final the following month.

"I came in for the first Old Firm game and we won 4-2," he said. "My last game was the 1-0 defeat. You never want to miss those games. It's been tough not being involved in the big games but I've had major games down here as well, playing for Blackpool against some big sides." Read the interview in the Sunday Herald