Ian Williams has died after collapsing in training, the Championship club confirmed on Tuesday.
Doncaster prop forward Ian Williams, 27, who joined the Knights from neighbours Rotherham last summer, collapsed during a session at Castle Park and could not be resuscitated.
Williams, an Oxford graduate, made six appearances for his club, who said in a statement: “It is with great sadness that Doncaster RFC announces the passing of prop forward Ian Williams.
“Ian collapsed at training at Castle Park this morning and, despite the best efforts of the emergency response team, could not be resuscitated.
“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.
“The club will be making no further comment at this time.”
England forward Joe Marler expressed his sympathies: “Thoughts are with everyone @DoncasterKnight and the family and friends of Ian Williams.”