The American helped the Blues reach the 2009 FA Cup final and they have finished no lower than eighth in the Premier League during his time with the club.
"It's hard to speculate but my heart is there for the club," he said.
"It's a place I love to be. I don't want to leave. This game is a business sometimes so there is that side to it but I'm happy - I'm happier than I've ever been.
"Part of that is the fact that we've got an unbelievable coach but again things happen and times change. But the club always stays the same so I hope that I can be there."
