The 31-year-old has been reduced to the role of token squad player at Old Trafford after a string of abject performances under Jose Mourinho.
Herrera, speaking ahead of Spain’s friendly with England on Tuesday night, claimed Rooney’s long-career has inhibited his potency at Man United this season.
“Wayne’s been playing at the highest level from 16,” Herrera said.
“I didn’t reach the first division until I was 20; he’s got four years on me. All that adds up. Sunday, Wednesday, Sunday, Wednesday, national team, Euros, World Cup, competing, winning, again and again.
“Fifteen years at England’s biggest club has an impact; people need to understand that. And he never disconnects, even when he’s not playing. He’s there, talking about how we can improve.
“This is someone who is just three goals away from overtaking Bobby Charlton as the club’s [record] goal scorer. And yet when we play in the Europa League and the team win two penalties he gives the ball to Paul [Pogba] and Anthony [Martial] because they need the confidence. That is where you see what type of person he is.
“You see it in the dressing room all the time, too. If he is not playing he’s still there talking about how to improve, how we’re playing, what we can do to win. He has never disconnected. When I retire from football one of the things that will stay with me is Wayne’s class.
“Last year he rescued us at times. How do you say, ‘got our chestnuts out the fire?’ He did it in lots of games, and this year he will do the same.”
Most players – if not all – blindly express their support for Rooney when asked about the captain. “He’s a fantastic player,” they’ll say; “Rooney doesn’t need to prove himself,” says another.
Herrera’s remarks, therefore, signal a welcome change of tune. There is a logical explanation behind Rooney’s terminal decline for both club and country that more or less every player, pundit and manager fails to recognise.
The Spaniard, however, has hit the nail right on the head. Rooney, since the age of 16, has made no fewer than 42 appearances a season – always in the spot-light, always at the highest level. And at the age of 31, his legs have called time on an excellent career.