Andre Onana 'hasn't done enough' to keep his spot as Manchester United's No 1 next season and the club must buy a replacement, according to Ben Foster.
Onana, who joined in a £47million deal from Inter Milan in 2023, made a number of high-profile and costly mistakes over the last campaign and his future at Old Trafford has been brought into question with the summer window now open.
Indeed, United could be open to allowing him to leave before bringing in a new first-choice stopper, especially with back-up Altay Bayindir similarly failing to impress.
Cameroonian Onana kept just nine clean sheets in his 34 appearances in the Premier League, conceding 44 goals as the Red Devils stuttered to a 15th-placed finish.
Adding fuel to the fire, recent reports have linked United with a swoop for Aston Villa keeper Emiliano Martinez - and Foster believes the Argentine is a must-buy.
Delivering his verdict on Onana, Foster told talkSPORT: 'It's a brutal league, the Premier League, and I kind of think [over] the last two seasons that he hasn't done enough to prove that he is a Manchester United No 1.
'I think he's got ability and like so many other Man United players, he'd go elsewhere and probably flourish. I think that's probably going to be the case with him as well.
'If the opportunity does come to sign somebody like an Emi Martinez, they've got to go for it. He's still one of the best goalkeepers in the world.
'A lot of people said this season, probably not up to the standard of the previous two years, but still one of the best goalkeepers in the world.
'You've got to have a strong spine in any football team. If you get the goalie right, you get a couple of strikers in, Bruno's going to be staying now.
'It's a great start to the transfer window for them.'
According to Argentine outlet TyC Sports, United contacted Villa about a move for Martinez in January before deciding to keep faith in Onana. It has also been reported that the Red Devils will be interested in Martinez if he leaves Villa this summer.
Martinez, 32, looks set to be sold by Villa, who need to offload a prized asset this month in order to meet the top-flight's strict profit and sustainability rules.
He was moved to tears after Villa's final home game of the season - a 2-0 win against Tottenham - last month and appeared to bid farewell to supporters.
Martinez was then sent off in his final outing of the season after rushing out and clattering Rasmus Hojlund during Villa's defeat by United at Old Trafford.
Asked about his future ahead of Argentina's upcoming World Cup qualifiers, Martinez said: 'I don't know, I come here to play for the national team, and that's the only thing that matters to me right now. Do I want to move to a new club?
'The transfer window just opened, so there's still a long way to go.'