Cahill has yet to agree personal terms on an expected £7million move to Stamford Bridge, but Wheater is ready to step up should he leave.
"If Gaz does go, he's a great lad and a good friend of mine and we'll miss him," centre-back Wheater told the Bolton News.
"But I want to be playing and with him going it gives me a chance to get in the team and, hopefully, stay in it.
"I've been in the Premier League for a year now with Bolton and it's just nice to be playing in the Premier League week in week out and that's what I want to do now.
"Obviously there's going to be pressure and I need to play well to stay in the team."