MANCHESTER, England -- Manchester United manager Ole Gunnar Solskjaer has hinted at major changes over the summer, saying executive vice chairman Ed Woodward and the club's owners know the extent of the rebuild required at Old Trafford.

United ended the season 32 points behind champions Manchester City after signing off with a dismal 2-0 home defeat to relegated Cardiff.

It leaves Solskjaer with a mountain to climb to get the club back to competing for major honours, and he said the owners and the board knew the work that needed to be done.

"I've had loads of conversations and they've been up front and honest -- we know where we are," he said.

"The end of the season makes it clearer than when we had that great run of form. We played some great football at times, and towards the end we've seen that exceptional efficiency we had didn't last and they know we're in for a rebuild."

Solskjaer started his reign with 14 wins from 17 games in all competitions but ended the campaign with two wins from the final 12 matches.

United have not won for a month and have taken just eight points from the final 27 available to fall out of the race for the top four, eventually finishing sixth.

"We've been poor," Solskjaer said. "We've hit a brick wall towards the end of the season. It's very disappointing, and a big plus is that the season is over.

"We are too far behind where we want to be. We're five or six [points] behind third, fourth and fifth, and that's who we need to challenge next year."

Ander Herrera and Antonio Valencia ended their United careers against Cardiff, while there are doubts over the futures of Matteo Darmian, Marcos Rojo, Juan Mata, Eric Bailly, Alexis Sanchez, Romelu Lukaku and Paul Pogba.

Solskjaer is hopeful of finalising his squad before the players return to Carrington on July 1 but, following the defeat to Cardiff, the 46-year-old refused to go into specifics about what his rebuild could look like.

"It's going to be a very important preseason for us," he said. "David [De Gea] has got one year left and we want to extend with him and we're in talks, and let's hope it will get sorted.

"Alexis has a contract with us. I'm not going to speak about individuals."