Sammy Lee admits he's been worried about Bolton Wanderers' form since Christmas last season.

Abandoning Sam Allardyce's 4-3-3 system for a more traditional 4-4-2 has confused fans and left players like skipper Kevin Nolan, hauled off in a 3-1 loss at Portsmouth, admitting they are no longer sure of their role.

But Lee said: "When you get 69 per cent of your points before Christmas and only 17 points after, I identify that there is a problem. Maybe we were in a comfort zone, but I felt we needed to change.

"There's been a problem since the turn of the year. It's not something I've done overnight, or that I'm inflexible, but I'm not going to stick my head in the sand. People will question it but change had to be made.

"We're working very hard to rectify the problems that we have. It helps when you get results but this malaise has been there for some considerable time.

"Of course I'm not happy about losing matches, and I'm not happy about conceding goals. I'm not going to be so naive as to be gung-ho. It would be very remiss of me and I don't think the public would accept it.

"I can't see that I've confused anybody with shapes. It's about the players adapting and we have played 4-4-2 before."