Hartis enjoys working with the 33-year-old Argentina international goalkeeper, and has been impressed with his adaptability and work ethic.
According to a report in ESPN in July, Leeds – who will play in the Premier League next season after winning automatic promotion from the Championship – are interested in signing Romero in the summer transfer window.
Metro claimed last month that the 33-year-old is considering his future at Old Trafford due to David de Gea being picked ahead of him despite making mistakes.
Hartis told United’s official website about Romero: “He’s obviously an experienced goalkeeper. He’s an international goalkeeper who has played in a World Cup final. I’ve found him to be extremely hard working.
“Very robust emotionally. He turns up to work every day and looks to better himself. Even now, at 33, he’s looking to make improvements to some fundamentals of his game, which is really refreshing.
“Good players adapt, so as players get a little bit older and the body slows down a little bit, the brain speeds up more. Sergio’s showing that adaptability.
“His thirst for knowledge means that he wants to come and see his clips after training, after the games, he’s still striving to improve, to be the best he can be.”
Good signing for Leeds United?
Romero is a very good and experienced goalkeeper who will make the current Leeds team better.
The 33-year-old would not be fazed at the prospect of playing in front of the Elland Road faithful, having played for one of the biggest clubs in the world in United.
However, it remains to be seen if Leeds are able to convince the Argentine to make the move to Elland Road this summer, with Kiko Casilla the first-choice goalkeeper at the club at the moment.
In other news, Report: 25-year-old a loan option for West Ham United