However, manager Michael Laudrup is keen to hand a new contract to the Dutchman's deputy Gerhard Tremmel.
Vorm, Swansea's player of the year last term, has been out for eight weeks after suffering a groin injury in the defeat at Manchester City in October.
Tremmel was thrust into the starting line-up after making only a handful of appearances during his 18 months in south Wales, and the German impressed with his displays in helping the Swans continue a good run which moved them into the top half of the table.
And while Laudrup will welcome Vorm's return, he is keen to reward Tremmel for his performances over the last two months.
He said: "Michel is back in full training so he is back in the squad. I don't want to say he will definitely play but Michel is ready.
"You always miss players when they are not there but people have asked if we've missed him because they think Gerhard has done well and I agree.
"Being a second goalkeeper is the most difficult position you can have because you hardly ever play and you have to wait and wait.
"And as a manager you don't know what the reaction will be when they come in because they can be rusty.
"But Gerhard has done well and it is very important to know you have a goalkeeper of quality when things happen. He has surprised me; I didn't know him a lot but he has done well.
"It is the last year of his contract and we'd be delighted if he can stay here for one more year. It will be up to him because he's had a taste and maybe he would want to go somewhere and be a number one - but I will be pleased to have him."
Sunday's clash with United kicks off the festive period for Swansea, who have suffered back-to-back defeats to Norwich and Tottenham.
Fixtures against Reading, Fulham and Aston Villa follow rapidly and Laudrup admits he would accept a defeat against Sir Alex Ferguson's men, if his side were to pick up a healthy haul of points elsewhere over the next 10 days.
He said: "It's as important to get points off Reading as it is against Manchester United.
"We would like to win but it would bring so much focus on us and what we need over the next 10 days is to be able to focus on these four games.
"If I knew we would get six or seven points in the other three games I would have no problem losing on Sunday. The problem is I don't know so we have to take one game at a time.
"The first game is against United, it's a big game because we are talking about the number one club over the last 20 years.
"They have a legendary manager and great players but it is still only one game so it is nothing special."
Laudrup also has winger Pablo Hernandez back in his squad after a thigh injury, but right-back Angel Rangel is set to miss out again with the calf injury that saw him miss the defeat at Spurs. Dwight Tiendalli is set to deputise again in his absence.