Suarez was suspended from all football activities for four months following his actions in a clash against Italy in the group stages in Brazil, having bitten Giorgio Chiellini on the shoulder.
That controversy did not prevent Barca signing Suarez from Liverpool, and the 31-year-old has gone on to enjoy a trophy-laden spell at Camp Nou.
The forward will lead the line - along with Edinson Cavani - for Uruguay and, speaking ahead of their opener against Egypt on Friday, veteran coach Tabarez insisted Suarez has matured since 2014.
"Suarez comes to the tournament as a very mature player. I have known him a long time, since 2006," Tabarez told reporters.
"What happened in Brazil is part of reality and has helped him mature. Luis is very smart and well prepared mentally.
"With all the good things he can do, he is key for the team."
16 - The last 16 Luis Suárez's goals for Uruguay have been scored from inside the box (five of them from penalty spot) since scoring in 2013 Confederations Cup vs Tahití. Killer pic.twitter.com/Bj6vO3ryCd— OptaJose (@OptaJose) 8 June 2018
Tabarez is taking charge of Uruguay at a World Cup for the fourth time, and the former Boca Juniors boss believes his side have the experience and quality to enjoy a fruitful campaign.
"It's a very compact group, with a lot of friendship and great leaders," added Tabarez, who acknowledged that many of his squad have had a tough season with their clubs.
"Getting here for us is already important. We arrived with the expectation of enjoying the World Cup and achieving great things.
"For that I have a group that is very well and the mentality is also very good.
"As for the preparation, we are in a similar situation to that of the European teams. They come after very strenuous seasons.
"The players had rest days, according to the requirement they had in their league and team. We never complain about the little time we have, each time it is less for us to be able to work with them."