Celta Vigo forward Iago Aspas has said that Frenchman Antoine Griezmann has 'a really tough decision to make' when it comes to his Atletico Madrid future.

Griezmann is believed to be Manchester United's leading transfer target ahead of this summer's window, and it is understood that the English giants are confident of enticing the attacker to the Premier League.

Aspas had an unsuccessful spell at Liverpool between 2013 and 2015, and the 29-year-old has suggested that he would not be surprised if Griezmann decided to remain in the Spanish capital.

"This depends on every player and the team. Because if we are talking about great teams like Manchester United, City, Arsenal or Liverpool then it is hard to say no if you play for a medium-sized club," Aspas told reporters. "However, Griezmann already plays for a great club with Atletico and sometimes it's really tough to make that decision."

Griezmann has scored 10 times in 24 La Liga appearances for Atletico this season, in addition to registering four goals in the Champions League.