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.