Celtic boss Ronny Deila says keeping his best players will take priority over acquisitions in the transfer window.
Chelsea striker Fernando Torres is understood to be set for a return to Atletico Madrid, according to Sky sources.
The Poland international goalkeeper has found himself largely on back-up duties at Old Trafford since linking up with the Red Devils in 2006.
Kuszczak has grown increasingly frustrated at his lack of opportunities and saw out the 2011/12 Championship season on loan at Watford.
At 30, he admits the time has now come for him to make a fresh start and he will drop into the free agent pool when his United contract expires.
"Last year I had a good chance to go back to my former club West Brom, where I enjoyed an excellent spell, or to Aston Villa," Kuszczak told Sky Sports.
"I have spent so much time on the bench in Manchester. I accepted it at first because I know how big a club they are, but it is not enough for me.
"I have decided to move and be a first-choice keeper. I do not want to be a replacement any longer."
Kuszczak would prefer to remain in English football, having spent the last eight years on these shores, but admits he also has options to explore in Germany.
"My family like England as much as me," he said.
"I think that I know the style of play and I have made my name here. But I have serious options in Germany to consider as well. My agent is working on a possible move to the Bundesliga."