Manchester United have continued their development under Ole Gunnar Solskjaer and look set to finish the 2020-21 season strongly. The Red Devils are certain to finish second in the Premier League, while they also have a chance of adding silverware to their ranks by winning the UEFA Europa League.But with Manchester City streets ahead of any other side in the Premier League, Solskjaer knows he needs to add a handful of quality players to his squad to compete on all fronts next season. His side have performed admirably for large parts of the current campaign, but their disastrous elimination from the UEFA Champions League group stages will play on the minds of the Norwegian.Manchester United preparing for important summer aheadManchester United have been linked with quite a few players in the past few months, as they look to add to their squad this summer. With the European Championships around the corner, it remains to be seen how they go about their business after the end of the current campaign.On that note, here are five players who have been linked with moves to Old Trafford this summer.#5 Pau Torres | VillarrealVillarreal CF v Granada CF - La Liga SantanderManchester United need a central defender to partner Harry Maguire, as Victor Lindelof and Eric Bailly continue to divide opinion amongst the Old Trafford faithful. Villarreal's Pau Torres could be the ideal man to add quality to their backline, with the Spanish international currently hailed as one of the best defenders in La Liga.When quizzed by Sport (quotes via Mirror) about being linked with Manchester United and Arsenal, Torres downplayed speculation that he is keen to leave Villarreal this summer."It’s a pride to see that your work is reflected in these kind of things that are talked about. But I face it with a lot of calm, I’m in a great club like Villarreal, and from the tranquility, I work every day."“I’m not thinking about that (taking a step forward) either, there’s still a long way to go, and my short-term objectives are the European semi-final and then to be available for the national team."🚨 Manchester United are still in the market for a new centre-back this summer, amid interest in Real Madrid's Raphael Varane and Pau Torres of Villarreal #mufc #mujournal [MEN] https://t.co/6v1MicuK7a— United Journal (@theutdjournal) April 26, 2021However, if Manchester United make a big offer for him, he is unlikely to reject a move to Old Trafford.#4 Kieran Trippier | Atletico MadridAtletico de Madrid v Athletic Club - La Liga SantanderManchester United have been linked with several right-backs to provide competition for Aaron Wan-Bissaka, and Kieran Trippier could be the ideal man to play such a role at Old Trafford.The Englishman sealed an unexpected move to Atletico Madrid in 2019 and has played an important role for Diego Simeone's side in the past two seasons.Manchester United are keen on signing Kieran Trippier and are monitoring his situation at Atletico Madrid.— Sky Sports Premier League (@SkySportsPL) December 9, 2020However, if he's offered a return to England, Trippier might be tempted to make the switch to Old Trafford. He turns 31 this year and his best days are probably past him, but his crossing ability and experience could be valuable additions to a Manchester United squad that currently lacks depth in key areas.