However, reports today suggest that Carlton Palmer has no plans to sell the former Yeovil man, who impressed in his first season in the Nationwide League.
Former England man Palmer said: ""We had an official bid for Tonkin, but that bid is now in the bin. "Whether it was for £75,000 or £125,000 I couldn't really say because I never looked at the figures.
"Dario asked about him during the summer and the answer was no then and it is no now."
Gradi, who has made securing a permanent left back his priority, has already failed in attempts to bring Stephen Warnock from Liverpool this summer and is unwilling to play Welsh international David Vaughan in defence.