Chelsea are considering a move for Manchester United forward Cristiano Ronaldo, who has informed the Red Devils he wants to leave this summer. (Athletic - subscription required)   Ronaldo, 37, could be willing to join Chelsea, but the Blues are yet to decide whether to make a formal offer for the Portugal international. (ESPN)     Barcelona president Joan Laporta and agent Jorge Mendes are also discussing the possibility of former Real Madrid icon Ronaldo making a sensational return to La Liga. (AS - in Spanish)   Ronaldo is also willing to take a significant pay cut to his £500,000-a-week