Former Liverpool player Lucas Leiva has announced his retirement from football, aged 36, because of a heart condition.
The issue was detected in pre-season testing with Gremio, the Brazilian defensive midfielder's boyhood club, for whom he re-signed in the summer.
Leiva was signed from Gremio for £5m by Liverpool in 2007 and went on to make 346 appearances in 10 seasons at Anfield.
"I can only be thankful for the career I built," Leiva said on social media.
"The day has come to say goodbye to the field. I confess that it came from greater forces."
Leiva added in a tearful news conference: "I'm ending where I'd like, not the way I'd like. I had a lot of hope that it could reverse, but it was not the case. My health comes first."
He initially struggled to break into the Liverpool midfield, but became a regular starter after the departures of Xabi Alonso and Javier Mascherano.
Leiva earned a League Cup winner's medal in 2012, despite missing the final with injury, and was an unused substitute in the 2016 Europa League final, which Jurgen Klopp's side lost 3-1 to Sevilla.
His tally of 247 Premier League appearances for Liverpool is the fourth-most by a Brazilian in the competition's history.
Leiva signed for Lazio in 2017 in a £5m deal and went on to win the Coppa Italia with the Serie A club. He also earned 24 caps for Brazil.