Former Manchester United captain Roy Keane has concerns about his old team ahead of the new season.
Keane played for the club during their Premier League golden era and was part of seven title triumphs.
But United have not been champions of England since 2013 and finished as low as eighth last season.
United have made four major signings since the end of the previous campaign, bringing in Dutch forward Joshua Zirkzee and defenders Leny Yoro, Matthijs de Ligt and Noussair Mazraoui.
But Keane believes that Erik ten Hag's side are still short in two key positions.
Speaking on Stick to Football, brought to you by Sky Bet, Keane said: 'It's always a worry for me about competing and I still worry about the spine of that Manchester United team.
'For all the nice play they have and good players, I still worry about the goalkeeper and striker.'
Keane added: 'On paper they have a decent squad, but the reality is when they've played games, and last year with their record in the league they were so open, If you're on about competing, I worry about the spine of the team.'
Cameroon goalkeeper Andre Onana started all of United's 38 league games last season, after signing from Inter Milan for £47million.
Keane was critical of Onana multiple times last season, labelling him as a 'disappointment' in December, before accusing him of 'messing around' during United's FA Cup semi-final against Coventry in April.
United also invested in a new striker last summer when they paid Atalanta £72m for Rasmus Hojlund.
The Danish frontman scored 16 goals in 43 United games last season but was still criticised by Keane for his inefficient finishing.
After Hojlund missed several chances in a 2-0 win over Wigan in the FA Cup in January, Keane said he would be 'fuming' if he was one of his team-mates.
United went on to lift the FA Cup last season, which seemingly saved Ten Hag from the sack following his dismal league campaign.
Keane is confident that United's league performance will be improved in 2024-25 but he is not expecting a title challenge.
'I fully expect United will do a lot better than last year,' he added on this week's episode of Stick to Football.
'They can't finish eighth again, can they? They can't be that bad. But we are talking about fourth here.'
Podcast host and fellow ex-United star Gary Neville then claimed that his main worry ahead of the new season was about injuries.
Neville said: 'Injuries are the massive thing for Manchester United. The left back is a problem because if [Luke] Shaw is out the drop off is massive. I do think they'll get into the top four if they stay clear of injuries.'
United will be without Shaw, Yoro, Hojlund and Tyrell Malacia when they kick off their new Premier League campaign on Friday night.
That will be United's second game of the season after they held Manchester City to a 1-1 draw in the Community Shield at Wembley, before losing 7-6 on penalties.
Despite that defeat, Neville believes that Ten Hag will have been pleased with what he saw from his team against City, especially in midfield.
'There was a massive difference last year,' Neville explained. 'They played Casemiro sitting on his own, with no one alongside him, and they had basically [Mason] Mount and [Bruno] Fernandes right in front, and then they had the two wide players high.
'That is not what they are doing now. They are putting [Kobbie] Mainoo alongside Casemiro and then they are playing narrow with Mount and Fernandes. I'm not saying it's a system, I can't see a balance, but he's got an interesting four players that he might try and go with, with some sort of split striker. I think he'll like what he'd have seen against City, in the sense that they can play with each other, and they can also be a bit narrow and compact.'
Roy Keane was speaking speaking on Stick to Football, brought to you by Sky Bet. Watch the full episode on Youtube