The 22-year-old is currently on a loan deal from Wolverhampton Wanderers that will run out in January.
"We're working really hard to do that (extend the loan deal)," BBC Sport quotes Fenlon as saying. "Leigh wants to stay to the end of the season and it's important that we get that done.
"We're confident we can get him to the end of the season. After that, I'm not sure, but I'm confident we can hang on to him till then.
"He's playing really well for us and working hard for the team and we want to keep him."