David de Gea has undoubtedly been Manchester United's best player this season, with consistently fantastic performances earning them countless points.
His goalkeeping exploits have earned him a place in the Premier League Team of the Year, ahead of stoppers such as Thibaut Courtois and Hugo Lloris.
But, his performances have also attracted the interest of Spanish giants Real Madrid, who have been linked with replacing long-time captain and legend Iker Casillas.
With just over a year left on his current contract - and a new deal not yet agreed - De Gea is seen to fit the bill perfectly at the Bernabeu, and there is potential he could be about to request a transfer.
Should he do so then the Red Devils will want to cash in on the Spain international this summer rather than lose him on a Bosman free transfer next season. So if De Gea does leave, who will replace him? A few names have been linked with the number one jersey at Old Trafford for next season.
Despite Spurs missing out on Champions League football and perhaps European football altogether depending on the finish to the Premier League season and the outcome of the FA Cup final between Arsenal and Aston Villa, Hugo Lloris has been a shining light for Tottenham this season.
Himself, along with Harry Kane have been stand-out players for Spurs, and with De Gea potentially leaving, he has been touted as a perfect replacement for the Spaniard, and a £30 million fee has been rumoured to be enough to tempt Daniel Levy into selling.
The France international has been largely impressive since his £12.3 million move from Olympique Lyon in 2012, with his sweeper-keeper style proving effective for Spurs when playing a high defensive line.
His pace is a valuable asset, not to mention his shot-stopping ability - up there with De Gea's - and his experience both internationally and at club level could fit Manchester United very well. Not to mention that he's 28, so as a goalkeeper he has plenty of years left at the top level.
The Bosnia and Herzegovina international has been fantastic at the rearguard for Stoke City in recent years, and has been a factor in the club's impressive defensive records since their promotion to the Premier League.
His consistency and physical prowess has been noticeable, and bodes him well for the physical nature of the Premier League. At 6ft 6in he is an imposing figure in goal, and looks dominant from set pieces and aerial battles in general.
His shot-stopping is also very good, not to the level of David de Gea or Hugo Lloris, but still he is a very accomplished goalkeeper. With his contract running till the end of next season like De Gea, a move could be on the cards and a major fee would not necessarily be the case.
A less likely replacement, as it would be very unlikely for Jose Mourinho to allow a top-quality goalkeeper like Petr Cech to join a potential title rival like Manchester United. But, with the 32-year-old almost certain to leave in the summer - especially with him playing second fiddle to Thibaut Courtois this season - his attributes would be well-suited to play for the Red Devils as their number one next season.
A top-drawer Premier League goalkeeper ever since his move to Chelsea from Stade Rennais in 2004, Cech has won numerous honours with Chelsea, including four Premier League titles, four FA Cup winners medals and a Champions League title in 2012.
His form over the past ten years of being Chelsea's number one has been outstanding, and puts him amongst the best goalkeepers in Premier League history.
With his Chelsea days numbered, he has been linked with many clubs around Europe, including Arsenal, PSG and Besiktas. However, with David de Gea potentially Real Madrid-bound, a position at Manchester United could definitely be tempting for the Czech Republic international.
Should Mourinho allow Cech to join their Premier League rivals, his all-round game could be a great replacement for De Gea. And his experience could be vital in United forming a serious title challenge next season.
Despite this, it is unlikely this will happen as Mourinho would be very unlikely to let quality players join rivals, with the exception being Juan Mata's move to Old Trafford in January 2014.