The midfielder, who recently returned from a ban after stamping on Dele Alli, was this time playing peacemaker at the club's training ground.
It had been reported Shelvey had been forced to wear his hand in a cast after an incident earlier this week.
And according to The Sun, the injury was due to the 25-year-old breaking up a fight between Mohamed Diame and captain Jamaal Lascelles.
The duo reportedly swapped insults before squaring up to each other during a fiery session at the club's Darsley Park training complex.
Lascelles is said to have called Diame “lazy” on numerous occasions, forcing the midfielder to respond with an insult of his own.
As the incident escalated, the pair apparently squared up to each other, leading Shelvey to try and intervene.
The former Liverpool midfielder was caught in the flurry of punches and believed he fractured his left hand.
Shelvey immediately went for treatment and will be monitored before his team’s fixture at Southampton next Sunday.
Thursday’s incident came shortly before it was announced skipper Lascelles had signed a new six-year contract on Tyneside.
The 23-year-old has agreed fresh terms to keep him at St James’ Park until 2023.
Rafa Benitez will be hoping the incident is quickly forgotten about before the trip to St. Mary's after the international break.
