Horsfield is on the Bramall Lane transfer list

Warnock's warning came after a surprise move to Celtic fell through for the transfer-listed 33-year-old who cost the Blades �1.2m from West Brom in May.

The Blades boss told the Sheffield Star: "We won't be giving Geoff away for nothing, definitely not.

"I'm sure he won't have a problem finding somewhere, but it seems Celtic no longer want him."

Bhoys boss Gordon Strachan appears to have turned his attentions to Burnley striker Kyle Lafferty

Horsfield has been told he has no future at Bramall Lane and Warnock accepts his stance over the price tag has forced Strachan to look elsewhere.

Warnock added: "I don't know what has changed Celtic's mind, but if they've gone for the lad from Burnley, I can't see them going for Geoff as well."

Horsfield was sent out on loan to Championship strugglers Leeds last August but the spell was terminated early and he returned to Sheffield United on 2 January.