The Belgium midfielder expects more signings to arrive this summer.
"Maybe there will be some transfer activity, because there are always names, especially with Chelsea. Everybody knows (owner Roman) Abramovich and the club. They have bought many players. You are never sure of your place in the team.
"You have to be 100 per cent always. Even if there are no incoming transfers, you still have to be like that, and it keeps you on your toes."