Cahill has battled himself into the England squad after impressing for Bolton Wanderers [GALLO/GETTY]

England defender Gary Cahill is on the verge of becoming a Chelsea player after passing a medical, said the Premier League club's manager Andre Villas Boas.

After days of negotiations over the Bolton Wanderers centre back's terms, the deal now looks a formality after the medical at the London club's training ground earlier on Saturday.

"Gary passed his medical and should be our player soon," Villas-Boas was quoted as saying by the BBC after his side's 1-0 defeat of Sunderland which consolidated fourth place.

The 26-year-old, who has seven caps and will cost Chelsea about $10.7 million according to British media reports, will link up at Chelsea with England skipper John Terry and looks set to replace Alex.

Media reports say the Brazilian defender, who asked for a transfer due to a lack of first team opportunities, could join
fellow west London side Queens Park Rangers.

Cahill joined Bolton from Aston Villa in 2008 with his career apparently going backwards but he has developed into an
outstanding defender even though Owen Coyle's side have struggled all season.

Chelsea have swooped with Cahill out of contract at Bolton at the end of the season. Tottenham Hotspur had also previously shown interest in the defender.

He will now compete with Brazilian David Luiz to be Terry's central defensive partner with Cahill fighting for a place in
England's Euro 2012 squad.