Doncaster Knights have announced the passing of prop forward Ian Williams at the age of 27.
The RFU Championship side have said that Williams collapsed during training on Tuesday morning and despite the best efforts of medical staff and an emergency response team, he was unable to be resuscitated.
A statement on the club's website said: "It is with great sadness that Doncaster RFC announces the passing of prop forward Ian Williams.
"Ian joined the club in summer 2017 from Rotherham Titans and quickly became a well-liked member of the Knights squad making six appearances for the club.
"We extend our deepest sympathies to Ian's mother Pippa, father Phillip and sister Helen and are working with a counselling team in the best interest of Ian's teammates."
Chief executive Gavin Baldwin added: "Ian was a prop with plenty of his career ahead of him, this is a sad loss for Doncaster's sporting community."
Doncaster currently sit in fourth place in the 12-team table.