The 29-year-old Lockyer was carried away on a stretcher and at the time the score was 1-1 at the time. The game was eventually abandoned.
The Premier League match between Bournemouth and Luton Town was suspended midway through the second half on Saturday after their captain Tom Lockyer collapsed on the field. Both teams left the field while Lockyer received medical treatment for around seven minutes at the Vitality Stadium. (More Football News)
The 29-year-old Lockyer was eventually carried away on a stretcher. The score was 1-1 at the time.
Lockyer had fallen to the ground without any other player near him. Players from both teams were alert to the incident and called for help. Luton manager Rob Edwards also ran onto the field of play.
However, his club have confirmed that Lockyer is stable. The club went on to confirm that he suffered a cardiac arrest on the pitch during the abandoned Premier League match at Bournemouth.
Luton said Lockyer was "stable and currently undergoing further tests".
"Our medical staff have confirmed that the Hatters captain [Tom Lockyer] suffered cardiac arrest on the pitch, but was responsive by the time he was taken off on the stretcher," Luton said.
"He received further treatment inside the stadium, for which we once again thank the medical teams from both sides.
"Tom was transferred to hospital, where we can reassure supporters that he is stable and currently undergoing further tests with his family at his bedside."
The Premier League said in a statement: "The match between AFC Bournemouth and Luton Town FC has been abandoned due to a player medical incident.
"Our thoughts are with Tom Lockyer and all players involved in today's match."
A statement released by Luton Football club called for players, staff and supporters "to come together" in support of Lockyer and his family.
"We are sorry to all supporters present that players from both sides were in no state of mind to continue with the game after seeing their much-loved team-mate and friend taken off like that and staff could not carry on with managing the game in such circumstances," Luton said.
"We thank everyone for the wonderful applause and singing of Locks' [Lockyers'] name inside the stadium at such a difficult time."
(With AP inputs)