Former Blues striker Tony Cascarino criticised Werner's performance in their Champions League win at Rennes in midweek.
“Well, Timo Werner has had a stinker tonight," Cascarino said on talkSPORT 2.
“His touch has been all over the place. He's not controlled it. All his lay-offs have been given away.
"I certainly hope Frank Lampard doesn't think he's going to play like this against Spurs at the weekend."