Romelu Lukaku's relationship with Manchester United continues to deteriorate as he looks to secure a move away from the club.
The striker trained with former club Andrlecht when United's squad was given the day off on Monday but failed to report back for training at Carrington the following day.
His absence from the club less than a week before their opening game of the season against Chelsea is expected to cost the Belgian two weeks wages.
It also comes just a few days after he reportedly angered Red Devils boss Ole Gunnar Solskjaer by publicly sharing results of a speed test undertaken by the first team in a Twitter post, which was later deleted.
With a growing rift between the striker and his manager, it is also understood that the 26-year-old's relationship with team-mate Paul Pogba has also suffered in recent months.
In addition to reports that the two players were involved in an exchange of words last season, The Athletic claims that Lukaku is unhappy with the way United have handled Pogba's own transfer situation.
According to the publication, the Belgian striker feels that Red Devils boss Solskjaer has 'indulged' Pogba's repeated suggestions that he is looking to leave the club amid interest from Real Madrid .
Earlier in the summer, Pogba hinted at a departure by telling reporters in Tokyo that he wanted "a new challenge somewhere else" before the Frenchman's agent, Mino Raiola, confirmed his clients intentions to leave in an interview with The Times .
Meanwhile, Lukaku has largely remained quiet on his intentions for most of the summer and feels he has acted professionally, which has reduced the amount of time he could spend training with potential new clubs.
Both Juventus and Inter Milan have made attempts to sign the 26-year-old but have been unable to finalise a deal, with United looking to recoup the £75million they spent on the player in 2017.
Inter have seen two offers rejected for the former Everton man while the Italian champions also failed in a bid which would have seen Paulo Dybala head to Old Trafford.
Lukaku has scored 42 goals in 96 appearances for United since making the switch from Goodison Park two years ago.