Sergio Aguero is changing his game under Pep Guardiola, according to former Manchester City striker Uwe Rosler.
The City striker's future is unclear under Guardiola, after he lost his starting berth to Gabriel Jesus in January before regaining it when the Brazilian fractured his metatarsal.
However, Aguero has risen to the challenge since coming back into the team last month and in his appearances in 2017, the Argentina international is running further and putting in more sprints than in the previous four years.
"When you compare Aguero from last season to this season, you can see a massive change," Fleetwood Town manager Rosler told Goals on Sunday.
"A change in terms of courage, high-speed running and a willingness to counter-press. Plus, he still scores goals. You can see Aguero is trying to buy into the ideals of Guardiola.
"What he does off the ball this year, is far more than he did last year."
Aguero is due to meet Manchester City officials to discuss a new contract at the end of the season and has confirmed he wants to stay at the club.
Guardiola has also spoken publicly of his desire to keep the striker and Rosler thinks it would be a mistake for both parties if they were to part ways.
"I would never lose him - I'm a big Aguero fan," Rosler said.
"When you have someone like him in your squad and you're aiming for titles on every level, you can't let somebody go like him.
"In a club like Manchester City, there is no player certain to start every game. You need to be competitive on all fronts. There has to be rotation, especially when you see the pace at which Manchester City are playing at now.
"The pace of their game with Liverpool was unbelievable, breath-taking. You need two world-class No 9's - and Aguero is one of them."