Cesar Azpilicueta believes John Terry is as good a player as ever but admits he is unsure over the Chelsea captain's future.
Terry claimed after the 5-1 FA Cup win over MK Dons that he would leave Stamford Bridge at the end of the season, though the club responded by insisting a new contract could yet be agreed.
The 35-year-old claimed following the 1-1 draw with Manchester United on Sunday that there was no communication with the club over a new deal, despite stressing that he was eager to stay.
Azpilicueta is adamant Terry has not suffered a decline this season but is in the dark over plans concerning his captain.
"It's a situation between him and the club. I don't know what's happening," he told Standard Sport.
"But since I arrived at Chelsea I have learnt a lot from him. I have played alongside him on the left for most of the time, even in training.
"For me, I see no difference in the way he's performing on the pitch, the way he's playing and he is giving everything for the team as always."
Chelsea's defence was dealt a blow on Sunday when Kurt Zouma suffered what looked to be a serious knee injury, with Gary Cahill - who had been linked with a potential exit during the transfer window - brought on to replace him.
Azpilicueta has no doubt Cahill can fill the void left by the young France international, adding: "Gary is one of the veterans of the team. We know his quality and in this squad, it is always important to be ready.
"We need everybody, we have big games coming up and all of us have to be ready.
"Kurt got injured when he landed. I didn't see it live, but we hope to have him back on the pitch soon.
"He is a young player but has been doing really well for us this season. It's his second year with the club and he has been improving with every game."