Messi has been in predictably scintillating form this season, and has relished a return to the centre forward position for Barcelona. The Argentinian has scored 41 in in all competitions and bagged 14 assists.
In an interview with 90 Minutes Fox, Ruggeri said:
"Do you think Barcelona will lose the Spanish championship if Messi doesn’t play again?
"Messi can call the Barcelona president and tell him ‘this is my World Cup’; I’m going to dedicate myself to the national team."
Messi is yet to win silverware with the Argentinian national team, and was brought to tears when his side lost 1-0 to Germany in the 2014 World Cup final. To win the World Cup this year will top off Messi's fantastic career.
"He [Messi] must also call the national team coach and tell him that he is going to be completely concentrated on the World Cup," Ruggeri continued.
"Before Mexico 1986 [the year Ruggeri won the World Cup with Argentina] we had 65 days to focus, 65 days before the World Cup we were all together.
What do you think the rest of the players are going to do if Messi goes to focus with the coach?"