Inter head coach Antonio Conte believes star striker Romelu Lukaku must train more to be in great shape due to his physique.
A club-record signing from Manchester United before the transfer window shut, Lukaku returned to the line-up after missing Wednesday's Champions League defeat against Barcelona due to a muscular problem.
Asked about Lukaku, Conte admitted the Belgian's big body requires special attention but that the striker is more than willing to put in the hard yards.
"Romelu is definitely a player that must train more, because being a player with a massive body he needs to train, to play, to be in great shape," Conte said.
"In this beginning of the season he had this back issue, now he's been dealing with this other quadricep issue since the game against Lazio.
"But I think he gave everything, it's inevitable that against Barcelona we didn't have Lukaku and it was important to have him. And we didn't have him.
"However, Romelu as well was very committed today, he tried to do his best, and now let's hope he can leave these little issues behind him and be at his 100 per cent."
Lukaku has scored three goals for Inter since arriving from United and has quickly struck up a strong relationship with Conte.
"My relationship with Conte is very strong," Lukaku told DAZN in September.
"He is a coach who really helps me. At the age of 26, I want a coach like this, who motivates and helps me every day.
"I am very happy to be here and to be working with him."
After winning their first six games of the Serie A season, Sunday's 2-1 loss to Juve has seen Inter drop down to second in the league, one point shy of the league leaders.