"We had to get that goal that mattered," was manager Sir Alex Ferguson's reasoning on Friday for the decision to substitute the England striker in Wednesday's 2-2 draw at West Ham United.
"As far as taking him off the other night, it was simple: he wasn't playing as well as Shinji Kagawa was. In so many games Wayne Rooney is better than most players. But on the night Shinji was playing so well."
The worrying thing for 27-year-old Rooney is that this in not just a one-off as it followed Ferguson's decision last month to drop him for arguably their biggest game of the season - the Champions League last 16 second leg against Real Madrid.
The stats tell one story, with Rooney netting 12 league goals to new Old Trafford darling Robin van Persie's 21, but that could be explained away by Rooney's deeper-lying position as more of an attacking midfielder than a centre forward.
Even if he has been moved for the benefit of the team, the fact a world-class striker has increasingly been cast in this role says more about his form than anything else.
Once an explosive force around the box, with a penchant for impossible strikes like the stunning overhead kick against Manchester City two years ago, he has begun to look laboured on the pitch and sullen when leaving it.
COLD WATER
It has not been all bad as he has scored key goals to help United in their charge towards a 20th league title, which they could secure on Monday if they beat Aston Villa and Manchester City lose at Tottenham Hotspur on Sunday.
He grabbed the winner in February's 1-0 victory at Fulham and two goals in January's 2-1 victory over Southampton but has been outshone by Van Persie even when the Dutchman was enduring his own dip in form.
Once a player who would cause a buzz of excitement among fans whenever he touched the ball, he is now more likely to hear them discussing the latest rumours that he could be on his way out of Old Trafford.
Reports from France have suggested he could join Paris Saint-Germain but Ferguson was quick to pour cold water on them.
"I don't think there is anything in it at all," he said.
The manager has already said Rooney, who has two years left on his contract, will still be at United next season but even he does not appear to be sure of the best long-term role for him.
"It's difficult to say," he replied when asked if the deeper position would be the best for him.
Once described by Ferguson as a "genius", the superlatives have been lacking for Rooney lately with some of his other team mates the more likely recipients.
Japan midfielder Kagawa has been in good form of late, playing either on the left or just behind a striker, and has been touted by Ferguson as one to watch next season.
"He's doing very well for us now," Ferguson said. "He has fantastic composure on the ball and his decision-making is good. He has a good selection of passes; he seems to always pick the more sensible pass.
"And he made a terrific first goal [a
