Wayne Rooney has expressed his concerns over former club Manchester United ahead of the January transfer window, as the Red Devils continue to pick up positive results in the Premier League without being fully convincing, according to their all-time top goalscorer Rooney. United returned to a top-six place after beating Newcastle United on Boxing Day but might need to add to their squad in January, claims the pundit.Man United have enjoyed the beginnings of a renaissance under Ruben Amorim in recent months, as the Portuguese head coach has seen new signings find their feet and performances take a step up from a dismal end to the 2024/25 season.The Red Devils currently sit sixth in the table – outside of the top five, likely to be the Champions League places, on goal difference – but recent injury issues have been compounded by a blow to captain and talisman Bruno Fernandes, which led Amorim’s side to look depleted in terms of numbers as they scraped past Newcastle 1-0 on Friday.Club legend Rooney has expressed his concerns over Amorim’s squad depth at present, fearing that they could slip down a congested Premier League table if investment is not made in the January transfer window.Appearing as a pundit on BBC Match of the Day on Saturday night, Rooney said: “I was worried when I saw the performance, if I’m being honest.“The manager changed the formation and he went with a back four, which a lot of people have been asking for. I know they didn’t concede a goal but they didn’t really look comfortable and Newcastle put them under pressure, especially in the second half.“And when I look at the squad and the bench, what they’ve got there, they really need players in to try and help them to challenge and get into the top four.“It’s great to see the young players on the bench and getting that opportunity, but it needs to be at the right time as well. It’s not sustainable at all. They need players in. They’ve obviously lost some important players and Bruno is a big loss.“They had 33 per cent possession in the Newcastle game – and I know when those fans go to Old Trafford they want to see the team with the ball, they want to see them entertaining, getting crosses into the box and getting shots off. It was a poor performance, but they found a way to win.”Looking for smarter football bets? Get expert previews, data-driven predictions & winning insights with GOAL Tips on Telegram. Join our growing community now!Head coach Amorim, however, has expressed a reluctance to panic buy in the winter window, suggesting that he will only add to his squad for the long-term and is prepared to “suffer” if the right players are not available.“What we cannot do is to reach January and try to do everything in urgency and make mistakes and then [it’s] ‘here we go again’ with a lot of mistakes,” Amorim said last week.“I’m not going to get [together] with [club chiefs] Jason [Wilcox] and Omar [Berrada] and say: ‘We need a lot of players.’ Because we have a plan.“If we have to suffer, the club comes first. Of course, we are in a moment where we need points but we need to find solutions and we are going to continue with our plan. You can feel in this moment that we are going to struggle, but we will see. We have to deal with it.”Add GOAL.com as a preferred source on Google to see more of our reportingUnited are currently without key players such as Fernandes and injured centre-back duo Matthijs de Ligt and Harry Maguire, while Mason Mount went off injured on Boxing Day. Three players are currently away at the Africa Cup of Nations in the shape of Bryan Mbeumo, Amad Diallo and Noussair Mazraoui. This meant that academy graduates Jack Fletcher and Tyler Fredricson appeared off the bench against Newcastle, while fellow youngsters Tyler Fletcher, Shea Lacey and Bendito Mantato were also amongst the substitutes.The 20-time league champions have been linked with midfielders such as James Garner and Conor Gallagher ahead of the January window, whilst the likes of Adam Wharton, Elliot Anderson and Carlos Baleba are long-term targets in the position.