Ronaldo wants to leave Manchester United this summer as he wants to continue to play in the Champions League this season.
However, several clubs have turned away from trying to sign him and Ronaldo was forced to start the campaign at Old Trafford.
Erik ten Hag is open to letting him go as long as a suitable replacement is secured and Manchester United are prepared to listen to offers for him.
And according to French outlet Foot Mercato, Sporting Lisbon have launched an audacious attempt to sign the forward this summer.
Ronaldo left the Portuguese giants to join Manchester United in 2003 and since then has become one of the greatest to players to the game.
With Manchester United ready to move him on, Sporting Lisbon are working hard to convince Ronaldo to return to his roots.
His wages are going to be an issue, but Sporting Lisbon are pushing to make a deal work and make the veteran think about a return.
A move to his former club would allow Ronaldo to compete in the Champions League this season.