Chelsea legend Clive Walker is not sure whether Mateo Kovacic could have the same impact from the bench as Ross Barkley.
Blues boss Maurizio Sarri has preferred to start with Kovacic in midfield with N'Golo Kante and Jorginho this season, leaving Barkley to be introduced from the bench, and the trend continued on Saturday against Manchester United.
Barkley came on off the bench and scored deep into injury time against the Red Devils to earn a 2-2 draw for Chelsea.
Walker has no doubt that Barkley can come on off the bench and make an impact, but he is unsure whether Kovacic could if the roles were reversed and the former Everton man started.
"With Barkley, I think he can make that difference. With Kovacic coming on as a sub, I am not sure he can make that difference", Walker said on Chelsea TV.
"We haven't seen it, because Kovacic generally starts.
"There is a question about his fitness because we haven't seen him play 90 minutes on a consistent basis."
Kovacic, who is on loan at Chelsea from Spanish giants Real Madrid, has not yet completed the full 90 minutes in any of his eight Premier League appearances for the Blues so far this season.
