The Championship rugby union match between Ealing Trailfinders and Cornish Pirates was abandoned on Saturday after Ben Grubb, the Pirates back‑rower, was knocked unconscious by a high tackle and later taken to hospital.

A spectator said Grubb was seen “convulsing on the ground” after what the Pirates called a “high shot” by the Ealing prop Kyle Whyte at the Trailfinders Sports Club in west London.

The home side, who are at the top of the Championship, were leading 12-0 in the 62nd minute when the 20-year‑old Grubb, who holds dual club registration and has made one appearance for Exeter, was injured.

A statement on the Trailfinders website said: “Ealing Trailfinders can confirm that today’s fixture against Cornish Pirates has been abandoned. This is due to an injury to Cornish Pirates’ Ben Grubb, our thoughts are with him, his family and Cornish Pirates at this time. We hope he makes a speedy recovery.”

On Saturday night, Cornish Pirates said Grubb had been discharged from hospital.

“Positive news, as Ben Grubb has been discharged from hospital following tests and scans coming back clear,” the club said in a statement. “Ben is on his way back to Cornwall and will continue his rehab at the club next week. Ben would also like to pass on his thanks for all the well wishes.”

Ethan Wetherell, a Cornish Pirates performance analyst, said: “From what we could see, as soon as he’d been hit he was basically knocked unconscious and then he was almost in a state of survival. Everyone was surrounding him and he wasn’t sure what was happening. I think at the time there was a bit of possible seizure on the pitch … as soon as they [medical staff] saw that, more help was brought.”

Grubb, a former British rowing champion, required lengthy treatment on the pitch before being taken to hospital in an ambulance. The players had left the field by then.

“They finally got him back up, after a while, but because of the state he was in he was pushing away everyone who was trying to help him,” Wetherell said. “Eventually the ambulance drove on to the pitch and got him off.

“I don’t think it was anything too malicious,” Wetherell said of the challenge. “It wasn’t a deliberate shoulder charge. He [Whyte] just tried to make a massive shot and got it pretty wrong … It would have been a red card, but that didn’t transpire because the game got called off.”

Brain injury is a particularly serious concern in rugby, with nearly 300 former players – including England’s 2003 Rugby World Cup winner Steve Thompson and Wales international Alix Popham – taking legal action against governing bodies due to damage suffered during their careers.