Manchester United may have been hoping that Roma’s Champions League elimination at the hands of neighbors Manchester City would aid their pursuit of long-time transfer target Kevin Strootman, but the Italian club insist the midfielder is not for sale. Strootman was left on the bench at the Stadio Olimpico on Wednesday evening, having only just returned to action from eight months on the sidelines with a serious knee injury. Despite his lack of fitness, United have been linked the player, whom manager Louis van Gaal coached with the Netherlands, since the summer. And some reports this week had suggested that the Premier League side’s chances of landing Strootman in January would be enhanced were Roma to bow out of the Champions League. Yet Roma general manager Mauro Baidissoni stressed after the loss that there had been no change in their stance.

“This is something I'm reading every day,” he told Sky Sports. “It is also something our president doesn't like to read every day. He made a statement a few weeks ago saying Kevin was not for sale but, to be fair, we haven't received any call from Manchester. We do not plan to sell him."

“I don't have a clue,” he added when asked whether Roma’s exit would mean they consider selling Strootman to United. “This is something you should ask Van Gaal or [United executive vice chairman] Mr [Ed] Woodward but we don't think we will sell our best players. Kevin is also young, not only a good player, he is a young player and we have a very long contract so we want to build our team around him.”

Strootman is not the only the only midfielder to be linked with a transfer to Manchester United of late. Rumors have increased that Benfica’s Argentina international Enzo Perez is prominent in Van Gaal’s thinking for January. The 28-year-old was pursued by Valencia in the summer, but the Spanish club balked at Benfica’s €30 million euros (£23.7 million) asking price. There was an expectation that Valencia would come back in for the player in the January transfer window, but now interest from Manchester United could complicate matters, according to Spanish sports daily Marca.

Valencia’s hand is strengthened by the close ties that exist between Valencia owner Peter Lim and Portuguese agent Jorge Mendes, which has helped several Mendes clients move to Valencia in recent months. United’s interest, though, reportedly could push the price beyond Valencia’s means. Perez impressed for Argentine en route to the 2014 World Cup final and has been a big success since moving into the center of midfield. Yet, he will turn 29 in February and Benfica’s asking price could be a hurdle for even the big-spending United.

Mendes also has a relationship with United, as demonstrated by his clients Angel di Maria and Radamel Falcao moving to Old Trafford in the summer. Another in Mendes’ considerable stable, Joao Moutinho, has now also been linked to Van Gaal’s men. The Portuguese playmaker moved to Monaco during their big splurge on the likes of Falcao and James Rodriguez in the summer of 2013. Yet the Daily Express now reports that Moutinho is eager to follow the Colombian duo in moving away from the principality. A transfer to United would be a considerable surprise, however, given that Monaco have advanced to the last 16 of the Champions League and United signed of Ander Herrera in the summer.

Rather than midfield, arguably the area of Manchester United’s squad most in need of strengthening is at center-back. All season, injuries have ravaged a backline that already lacked strength, with Chris Smalling becoming the latest casualty. Despite frequent speculation linked United with center-backs, Van Gaal insisted after the team’s win over Southampton on Monday that there was no necessity to enter the transfer market next month.

“Do we have to buy players? No. We have more than enough,” Van Gaal said, reports Sky Sports.

Bizarrely one of the defenders linked with United in recent days has been one of the stalwarts who left Old Trafford over the summer, Nemanja Vidic. The 33-year-old has endured a torrid time since joining Inter Milan and has found himself out of the starting lineup since Roberto Mancini took over as coach last month. Still, Vidic’s agent has unsurprisingly denied rumors of his swift exit.

“Not at all, they are all lies,” he told "Vidic has a three-year contract with Inter and does not move from Milan. It's almost useless to comment on the nonsense that is spread and I do not see a reason for him to be linked to other teams.

“There was little respect towards my client from the press. As soon as the Nerazzurri lost a few games, the press did not think twice to attack Vidic and point to him as the sole culprit. I repeat: he will not move from Inter.”