Former Chelsea defender Frank Sinclair has said that Nemanja Matic is "priceless" to the club.
The 26-year-old midfielder has been an influential figure for the Blues this season, making 25 appearances in all competitions.
Chelsea's only Premier League defeat of the season, which was at Newcastle United two weeks ago, came when Matic was out of the team.
"Matic is priceless," Sinclair told talkSPORT. "It's no coincidence that he didn't play in the one game they lost this season. He plays a big part.
"And in the last few games [John Obi] Mikel has come back in as well and they look even more solid with the two of them in there, and that gives Cesc Fabregas the licence to get forward and do his stuff further up the pitch."
Matic returned to Stamford Bridge from Benfica in January.