Journalist James Copley admits he is 'very concerned' about Sunderland's squad depth, following their 1-0 defeat to Middlesbrough in the Championship.

The Lowdown: Black Cats beaten at Boro

The Black Cats made the short trip to the Riverside Stadium on Monday evening, looking to continue what has been a promising start to the season.

Unfortunately, Tony Mowbray's side were never at the races, with Riley McGree's solitary strike eventually proving to be the difference between the two teams.

The defeat leaves Sunderland seventh in the Championship, and that's now two losses on the bounce.

The Latest: One key concern...

Writing on Twitter after the game, Copley and a fan agreed on a promising note - all three of the Black Cats' defeats have come against some of the favourites for promotion - Boro, Sheffield United and Norwich.

However, the Sunderland Echo reporter did note one big concern after Ross Stewart pulled out injured in the warm-up...

"I’m still very concerned about the depth of this squad."

The Verdict: Potential issue in a long season

Having plenty of squad options is essential in a league as relentless and competitive as the Championship, with fatigue and injuries inevitable during the season, especially with a winter World Cup truncating things this time around.

Sunderland's lack of depth does, therefore, feel like a concern, with Stewart's injury absence on Monday perfectly highlighting the difference in quality between him and the backup attackers.

The talisman was a huge loss and the Black Cats were toothless without him, mustering only two shots on target, and there are fears he could miss 'several weeks'.

It could be that January reinforcements are needed to bolster Mowbray's squad or it may be tough to envisage them mounting a genuine promotion push this season.