Collins has been allowed to rejoin Barnsley after two months at the Greenhous Meadow during which he made 10 appearances, the most recent coming at the start of November.
And, with the loan window having closed last week, manager Graham Turner is now starting to rue that decision after it was confirmed Bennett's back injury looks likely to curtail his stay, with his initial month-long agreement with Sheffield Wednesday expiring this weekend.
"I need to talk to Sheffield Wednesday about Julian," Turner told Town's official website. "The physios, medical people (from both clubs), have already been in touch with each other. They know what's going on. It doesn't look too promising that he will be with us after this weekend simply because of his back injury.
"His time looks as though it's up here and it's a pity because he is a very experienced player. It's unfortunate that we've obviously let Lee Collins' loan lapse before we knew about Julian."
Turner added: "I can't do anything about it until January so that's one of the problems we've got to face. We've got players who are flexible in where they play, Rob Purdie, Joe Jacobson and Jermaine Grandison can all play in different positions. (There's) Connor Goldson and one or two of the other younger players like Ryan Woods."