Fulham boss Lawrie Sanchez has warned current first-choice goalkeeper Antti Niemi not to rest on his laurels.
Sanchez said: "Antti's still a top goalkeeper and he showed that in the last two games, but before that he was responsible for some of the goals we let in and everybody knows that.
"Keller felt some pain in his upper arm after a training session before the Derby game and it turned out he has damaged some tendons. That's why Antti got back in but I had dropped him and he knows why.
"Now I've been telling him to keep showing why he's regarded as the number one here and at the moment he's certainly doing that again."