He won 21 games pitching for the Cubs most of the past three seasons before Chicago dealt him to the Texas Rangers at last July's trade deadline.
Garza will push his warm wishes for his former teammates aside this season, however, insisting he would have extra motivation whenever he takes the mound to face the Brewers' division rivals.
"I wish them the best," he said. "But I like where I'm at, and I'm going to try to kick their teeth in every time I get a chance."
Garza ended up going to the Brewers for four years and $50 million after going a combined 10-6 with a 3.82 ERA over 24 games with the Cubs and Texas in 2013. While he said he savored his time at Wrigley, he voiced some rancor about how the Cubs' front office treated him.
Speaking to the Chicago Sun-Times this week, Garza was still bitter about being on the trading block for a good part of his three years in Chicago and seeing his on-again, off-again contract talks with upper management ultimately prove fruitless.
"They finally put it like, 'Hey, we're rebuilding, don't get comfortable,'" he said. "You just take it with a grain of salt and enjoy the time while you're there.
"I'm just a pawn. It's just playing a chess match. You've got your king and your queen you have to protect, and then you put the pawns in. That's us."
Garza called it a learning experience.
"I dealt with a lot there," he told the Sun-Times, "a lot of positives and some negatives."
Several of Garza's ex-Chicago pitcher teammates brushed off Garza's comments when asked about them Friday, saying they were no big deal.
"Garza wants to kick everyone's teeth in when he plays them," staff ace Jeff Samardzija said. "Above all Garza plays baseball to compete."
Asked if he was bothered by Garza's smack talk, pitcher Carlos Villanueva smiled and said, "Nobody pays that much attention when he says stuff like that. Obviously we want to kick his ass, too."
Garza is 67-67 with a 3.84 ERA in eight seasons with Minnesota, Tampa Bay, the Cubs and Texas. He was the MVP of the 2008 AL Championship Series, beating Boston twice while with Tampa Bay.
Garza has struggled this spring with numbers that show him with a 19.06 ERA, but he vowed Wednesday that they don't mean anything.
"I'll be ready when the bell rings," said Garza, who allowed 10 runs, six earned, and nine hits in a Los Angeles Angels split-squad's 12-2 win over the Brewers.
The Associated Press contributed to this report.