Sebastian Coates said it was an "easy" decision to leave Liverpool for Sunderland on a permanent deal.
The centre-back joined the Black Cats for £2m on July 1 to end a difficult four-year stint at Anfield, during which he struggled for form and battled injury.
Coates played only 12 league games in his first two seasons with the Reds before cruciate knee ligament damage while playing for Uruguay in August 2013.
He recovered to play briefly for his country at the 2014 World Cup in Brazil, and spent last season on loan at Sunderland in a bid for regular games.
The 24-year-old featured only rarely under Gus Poyet, but was used more often when Dick Advocaat took charge in March.
"It was an easy decision to come back because I know the manager, my teammates, the club and the supporters," Coates told the Sunderland Echo. "It was really easy.
"The last month of the season changed everything, but that's football.
"It was a great month for me and of course that was the best bit of the season for me.
"It wasn't certain that I'd leave Liverpool this summer, but I always thought I'd have to speak with the club and see what the situation was.
"But I knew it was a great opportunity to come to Sunderland and play regularly in the Premier League. That's why I'm here.
"When I first came here last year, I just did it to play games and recover from my injuries.
"I didn't think about making it permanent. For me, it was a tough season, but playing in the last six games was great."