Relegation is all but a certainty for Wilder’s side, which could look very different next season, the coach admitted.
“There’s so many things we need to address,” he told Sky Sports. “We need to keep our best players. There’s a couple who need to go. They have to go at the end of the season.”
“I’d like to shake it up quicker. We looked like we’d run our race.”
Wilder, whose own future at United is uncertain, acknowledged the difficulty of competing with eight players absent, including five defenders.
“The hand I’m getting given at the moment is a tough one, with some of the players we have to go with,” he said.
“I haven’t really got an answer for anybody. We have to regroup and go again. It’s a tough gig.”
James Ward-Prowse put Southampton ahead from the penalty spot shortly after the half-hour mark on Saturday before Che Adams doubled the Saints’ lead early in the second half.
“We didn’t deserve anything from the game,” said Wilder. “They could have had three or four.
“We have to be at our best. The best players have to be playing to the best of their ability to be able to make it a tight affair or get a result.
“We looked off it and tired in the second half.”