Richard Keys has tweeted his belief that Everton should sell John Stones if they receive an offer of £35 million.
Chelsea have been credited with a strong interest in Stones by the Daily Mail, and they tried to sign the England international last summer.
At that stage, Everton rejected all offers for the 21-year-old, but Keys believes that the Toffees should be more willing to let the youngster leave now.
If anyone is prepared to pay £35m for Stones I'd take it - now. Someone has to teach him to defend - that won't be Martinez.— Richard Keys (@richardajkeys) January 28, 2016
Stones’ form has dipped recently, with Everton’s defensive issues continuing to plague their season.
The Toffees have conceded with great frequency, and they are currently stuck in 12th place in the Premier League table.
Martinez’s side were also dumped out of the Capital One Cup by Manchester City yesterday evening.
City beat Everton 3-1 to progress to Wembley, and Stones was played at right-back in the fixture.
Everton’s damaging defeat to Manuel Pellegrini’s side has put further pressure on Martinez, with the calls for the Spaniard to be sacked growing increasingly louder.