Daryl Janmaat will miss Saturday's crucial home game against Swansea City with the hand injury he suffered punching the dressing room wall at the St Mary's Stadium.
Janmaat – who had slipped in the build up to Southampton's second goal and limped off with a groin problem – lashed out in frustration.
And the 26-year-old's actions have left Rafa Benitez without another unwanted headache ahead of a must-win game for the relegation-threatened club.
Here we look at Benitez's right-back options for Saturday's game against Swansea:
Vurnon Anita was moved to right-back after Janmaat's withdrawal at the St Mary's Stadium, and he seems the most likely option for Benitez.
The midfielder had started the game at left-back, another problem position, and the 27-year-old has become something of a utility player for Newcastle.
But Anita – who was targetted by Norwich City earlier this month – is better equipped to play in midfield, and it's still not ideal.
Kevin Mbabu would be a natural replacement for Janmaat given that he's a right-back by trade.
But the 20-year-old – who impressed earlier this season playing at left-back – has been sidelined for several months with a thigh problem.
United manager Benitez has not put a timescale on his comeback, and it seems unlikely that he will be fit in time to face Swansea at St James's Park.
Jamie Sterry, a tough-tackling and attack-minded right-back, was pulled out of Monday night's Under-21 Premier League game against Brighton and Hove Albion in the wake of the injuries suffered by Janmaat at Southampton.
Tthe 20-year-old is another option for Benitez, though he lacks experience, having not been allowed out on loan this season.
That said, what the boyhood Newcastle fan lacks in experience, he would make up for in commitment.