Sunderland head coach Lee Johnson has admitted that Frederik Alves was not included in the club's match-day squad for their trip to Arsenal yesterday due to a lack of discipline in training.
Alves would have been hoping to make an appearance at the Emirates Stadium after featuring for the Black Cats in their previous League Cup clashes with Blackpool, Wigan Athletic and Queens Park Rangers.
However, instead of turning to the 22-year-old for inspiration in this fixture, Johnson opted to select Bailey Wright, Callum Doyle and Tom Flanagan in a three-man defence.
In Alves' absence, Sunderland were eliminated from the competition by Arsenal who cruised to a 5-1 victory in-front of their supporters.
Eddie Nketiah opened the scoring for the Gunners in the 17th minute as he fired past Black Cats goalkeeper Lee Burge.
Nicolas Pepe then doubled Arsenal's advantage before Sunderland pulled a goal back via a strike from Nathan Broadhead.
Following the break, Nketiah scored twice to complete his hat-trick whilst teenager Charlie Patino added a fifth for the Gunners in stoppage-time.
Making reference to Alves' absence after the game, Johnson revealed that the defender was left out of the team due to a lack of discipline.
Speaking to Chronicle Live about Alves, the Sunderland boss said: "With Frederik, it was an attitude error that knocked him out of the squad.
"A lack of discipline in training."
The Verdict
Having missed out on the opportunity to test himself against Premier League opposition yesterday, Alves will now need to step up to the mark in training if he is to force his way into Sunderland's side for their upcoming clashes with Doncaster Rovers and Sheffield Wednesday.
A failure to make a positive impression in the coming days may result in the defender being recalled by West Ham United in the January transfer window as he has struggled for game-time during his loan spell with the Black Cats.
Limited to just eight appearances in all competitions this season, the defender is currently behind the likes of Doyle, Wright and Flanagan in the pecking order at the Stadium of Light.
If Alves' stint at Sunderland is cut short by the Hammers, Johnson may need to bolster his options at centre-back in order to provide some extra cover for any future suspensions or injuries.