Swinton forward Will Hope says he waited for three hours for an ambulance while in "agony" with serious leg injuries sustained in Sunday's Championship match against Sheffield.
Hope, 25, suffered a broken leg, dislocated ankle and torn ligaments.
When an ambulance did not arrive, he said he was carried by team-mates onto their coach which took him to hospital.
Hope has asked for the Rugby Football League to address the issues he experienced.
RFL 'has strict medical standards'
And in a statement, the game's governing body said: "The RFL was contacted by Swinton on Monday regarding the circumstances surrounding Will Hope's injury, and has noted the player's comments on social media.
"Firstly, we send him our sympathy for suffering such an injury in the first match of the season, and wish him all the best in his recovery.
"We have contacted Sheffield Eagles for an explanation of the circumstances as they have been reported.
"While the delay before the arrival of an ambulance is beyond the control of the club, we have strict medical standards for all fixtures relating to personnel and facilities, with at least one doctor required to be present, and to be supported by the medical staff of each team."
Sheffield Eagles chairman Chris Noble added: "Firstly, everyone at the club wishes Will all the best with his recovery. Swinton are a great club and we know he is being well looked after.
"As per Will's statement, all the medical staff at Sheffield Eagles provided the utmost care for Will, and support to the staff from Swinton, whilst we waited for an ambulance.
"We are in discussions with St John Ambulance and Yorkshire Ambulance Service to find out why no ambulance arrived on site despite numerous calls to find out time scales."
Jackie Cole, Divisional Commander (South Yorkshire) at Yorkshire Ambulance Service NHS Trust, said: "We are very sorry for the distress caused by our delayed response to this incident.
"The call was received during an extremely busy period on Sunday and we were doing our best to respond as quickly as possible to all patients who needed our assistance.
"We would be happy to look into the specific details of this incident for the patient via our Patient Relations Team."
A St John Ambulance spokesperson added: "St John Ambulance were contracted to provide first aid cover for the crowd at this event.
"This arrangement did not include the provision of an ambulance or cover for injuries occurring to the players. Following one of the players sustaining an injury our first aiders worked with the club medical staff present to provide treatment.
"The patient was conveyed to a local hospital by the club. This was not a decision taken by St John Ambulance. We wish Will a speedy recovery. "
The RFL's medical standards document for 2019 outlines which medical provisions are mandatory at various levels of the English game.
In the second-tier Championship, full-time clubs must have at least a doctor and a physiotherapist present at first-team games.
For matches involving part-time teams such as Sheffield and Swinton, both clubs must provide either a physiotherapist, sports rehabilitator or sports therapist, while it is the responsibility of the home side for a doctor to be present.
'I cannot describe the agony and the anger'
Hope posted on Twitter: "To be treated like that, with my foot facing the wrong way for up to five hours because I 'wasn't a priority' is disgusting and I wouldn't wish that pain on my worst enemy.
"I cannot describe the agony I was in and the anger I still feel about the whole situation.
"If it wasn't for everyone at Swinton Lions, I'd probably still be laying on that stretcher in the corridor waiting for an ambulance.
"I'm sure if it was a Super League game, it would be different. It's actually laughable how bad it's become.
"The whole of Swinton Lions and Sheffield Eagles have been fantastic, I can't thank them enough. As well as everyone at Salford Royal Hospital - they've been brilliant."
Swinton chairman Andy Mazey added: "These athletes put bodies on the line for people's entertainment.
"I have communicated with the RFL operations team and (RFL chief executive) Ralph Rimmer and hopefully measures can be put in place to avoid this happening again."