United head to the Britannia Stadium on Sunday reeling from a turbulent week at Old Trafford, with talismanic striker Wayne Rooney announcing his desire to depart the club.
Sir Alex Ferguson's side will also have taken little confidence from their unconvincing 1-0 victory over Turkish champions Bursaspor in UEFA Champions League action on Wednesday.
However, Rio Ferdinand, Paul Scholes and Dimitar Berbatov are among the players expected to return for United on Sunday having been rested for the midweek clash.
And Pulis is anticipating a major threat from the visitors, with or without Rooney in their line-up.
"I think Sir Alex has paid us a massive compliment by resting so many players in midweek," Pulis told The Sentinel.
"Unlike quite a few teams who've faced United in the past few weeks, we will be facing as close as possible to what is their 'A' team.
"That will make it a much tougher game and we are under no illusions about the size of task ahead of us."
United have displayed lacklustre form so far this campaign and the Potters fans could be forgiven for feeling confident of an upset on Sunday.
But Pulis was quick to point out that the Red Devils are the only unbeaten team in the Premier League this season, and feels the commotion over Rooney's future will only have served to strengthen the resolve of the manager and players.
"There's no doubt about that," he added. "Sir Alex has seen it all before and that's one of the reasons I would say he is probably the best we've ever seen in this country."
When explaining the reasons behind his decision to leave United, Rooney implied the team no longer has the talent to compete at the highest level.
Pulis, however, feels Ferguson's developing squad should not be underestimated, adding: "Sir Alex has a lot of younger players there now and has a track record of bringing them through.
"I'm sure that's what he will be aiming to do and it's that kind of passionate drive that I admire most of all about him.
"It's incredible for a man who has already achieved so much, and at his age too. I'm just hoping to still be alive at 68."