Barcelona forward Lionel Messi played three games while carrying a kidney stone earlier this season, according to the specialist who treated him.
In December, Messi was ruled out of the Club World Cup semifinal victory over Guangzhou Evergrande with renal colic, a type of abdominal pain commonly caused by kidney stones, but returned for the 3-0 victory over River Plate in the final.
After the Club World Cup, Messi scored 12 goals in 11 games for Barca in all competitions before undergoing treatment last month, but Dr. Francisco Ruiz Marcellan, urology chief at the Instituto Dexeus, has said the Argentine played through the pain barrier in three of those matches.
"Leo Messi played three games with the stone in his kidney," Ruiz Marcellan told Catalan TV3 programme "Divendres."
"He played with tranquilisers as he had not yet expelled it."
Messi then underwent a procedure on Feb. 9 and missed two days of training in early February, also sitting out the Copa del Rey semifinal second leg against Valencia.
The following weekend he scored one goal and assisted two in a 6-1 victory over Celta Vigo at the Camp Nou.
While Barca never confirmed the precise nature of the treatment Messi underwent in early February, Catalan sports paper Mundo Deportivo reported that it involved extracorporeal shock wave lithotripsy (ESWL) -- a non-invasive procedure that uses high-intensity waves.
"It is a mechanical energy that generates the capacity to break up the stone," Ruiz Marcellan said.
The doctor warned that the problem could return for Messi in the future.
"With his genetic predisposition, it is very easy for him to have between two and eight stones in his kidney until he is 50 years old," Ruiz Marcellan said.