Newcastle's Steven Taylor is recovering in hospital after a reported training ground bust-up with Andy Carroll.
Magpies boss Mike Ashley and managing director Derek Llambias are to launch an investigation to discover exactly what happened at the Championship leaders' Little Benton training complex which has seen both players hospitalised.
Reports in Tuesday's tabloids have suggested Carroll, Newcastle's leading goalscorer, attacked club captain Taylor after the centre-back received text messages from the striker's former partner.
Taylor is said to be in a stable condition on the orthopaedic trauma ward at Newcastle General Hospital, while Carroll is also believed to have had an operation on his hand following the altercation.
Newcastle have yet to comment on speculation, with some reports saying Taylor could miss the rest of the season with a broken jaw.
However, Ashley and Llambias will be furious that a self-inflicted wound could wreck the growing feel-good factor at St James' Park.
The Magpies have attracted the wrong kind of headlines in recent years, most notably over the astonishing on-field spat between colleagues Kieron Dyer and Lee Bowyer, as well as Joey Barton's spell behind bars.
However, a new-found stability off the pitch in recent months and positive results on it had provided a welcome respite with the prospect of a swift promotion back to the top flight the main focus of attention.
The irony of the latest turmoil for the North East club is that Taylor was nearing the final stages of his rehabilitation from the knee injury which has sidelined him since January, and had hoped to play a part in the club's final few games of the campaign.
Carroll, who scored his 15th goal of the season in Saturday's 2-2 draw at Bristol City, has seen his fine form been rewarded this year by being included in Stewart Pearce's England Under 21 set-up.
However, the 20-year-old is facing a Crown Court appearance next month after being charged with assault following an alleged incident at a city nightspot in December last year.