Salter, 20, missed just five games in 2013, and is a product of the club’s academy system.
Head Coach Craig Sandercock said: “Liam has come a long way this year. He’s someone who we probably didn’t think would play every week.
“We knew that he was a good, solid player and that we might get 10 games out of him.
“But he really exceeded all expectations this year and, if he has a big pre-season and works on the areas we’ve identified for him to improve upon, then we’re really confident that Liam will be a great player for this club for many years to come.
“I’ve coached many young kids during my time and his attitude is as good as any that I’ve come across previously.”
Salter said: “The club approached me with regards to extending my deal and I had no hesitation in signing it. I’ve grown up supporting the club and to have the opportunity to play here is a real honour for me.”