Robinson arrived at Bramall Lane on a months loan from Premiership side Portsmouth until the end of January but has only made one first team start against Norwich City.
However wages could cause a problem for the cash strapped club, though the Welsh international has said that he would love to stay in South Yorkshire after completing a successful three month loan spell with Rotherham United earlier in the season.
"A permanent deal is not out of the question," Warnock told sufc.co.uk. "Ronnie Moore will tell you that Carl will fit in and is a good addition around the place.
"I'd like to see if Carl could play a part in the long term. I told him when he arrived he wouldn't play every game.
"He's made it clear he wants to join us, but he knows he has to come on our wage structure and Portsmouth know they would have to subsidise a move for this and next season."