The Edinburgh stand-off was released at the weekend to be part of the Scottish Thistles sevens side, which defeated Leicester in the final of the 125th Mathon Melrose Sevens. The talented former Biggar fly-half has always possessed some sublime skills and was again a star performer at the weekend, but after failing to make the professional grade with the Borders he has struggled for opportunities at Edinburgh after joining from Currie last summer.
Lynn Howells, the former Edinburgh coach, has offered him a chance, however, to continue his pro career with a two-year contract at Doncaster Knights, where former Borders and Scotland flanker Scott Gray now plays.
Warnock said: "It was Lynn who signed me at Edinburgh and I always got on well with him, and he'd been trying to get me down there on loan this season. I had only a year's contract at Edinburgh and I think it's fair to say I haven't managed to impress Andy Robinson to the extent that there's a chance of staying longer.
"I've played very little rugby this season and while I was glad to be involved with the sevens team, and it was fantastic to play again at Melrose and win such a great tournament, I want to be playing 15s regularly. I'm 25 and I just want to play rugby, so I'm enthusiastic about the move and what I could do at Doncaster. Northampton have run away with the Division One title, and Doncaster are currently fifth, just a couple of wins off second spot, but they are a very ambitious club and have big plans to join the Premiership."
He added: "I'd love to play for Edinburgh again before the end of the season and if Stephen Gemmell feels I helped the team then it would be fantastic to be part of the Scotland sevens team that plays at Twickenham and Murrayfield."