The pair, who work for British broadcaster Sky Sports, clashed on whether Ronaldo should be given an automatic place in the starting XI due to the accolades he has earned throughout his career.
Ronaldo was only brought on just after the hour mark at Stamford Bridge, with interim coach Michael Carrick — perhaps under instruction from incoming interim head coach Ralf Rangnick — instead opting to start Marcus Rashford, Jadon Sancho and Bruno Fernandes in attack.
“Why Carrick is trying to give him [Ronaldo] a high-five [as he walks down the tunnel], I don’t know,” former United captain Keane said. “Let him get down the tunnel, there is nothing wrong with a player being upset. Ronaldo has not come back to Manchester United to sit on the bench. What is the point?
“He is a world-class player. His stats since he came back to the club are okay, he’s got some goals and some assists. This idea that he is going to start closing people down — he’s not. Sometimes, you have to work around a superstar.
“I’ve played with players who don’t do the bit you hope — the [Eric] Cantonas of this world — but you forgive them because they score the winning goals in tight matches. Ronaldo has to be in the starting XI.”
Carragher doesn’t expect Rangnick to keep Ronaldo on the bench when he takes over, but the former Liverpool defender said the “idea that Ronaldo has to start every game and play every minute of every game, I don’t think is right.”
“Going away in big games, I can understand why Michael Carrick never started him against Chelsea,” Carragher added.
“Now, Ronaldo’s not the player he was. He’s still obviously delivering for Man United in terms of goals, but I don’t think it should be a big story if Ronaldo doesn’t start every game or, at times, comes off in a game of football.”
The debate around Ronaldo’s inclusion in the starting XI will inevitably continue, with Rangnick preferring that his teams press with intensity high up the pitch, something Ronaldo hasn’t been instructed to do for a number of seasons.
Ronaldo’s goals since his return to Old Trafford have been a rare shining light in an otherwise drab season for United so far, but perhaps Rangnick’s most difficult task will be finding a way for the rest of the team to function around him.