Minor-league pitchers Lucas Braun and Carter Holton are heading to Kansas City to complete the trade.
Thomas, 30, has hit 10 homers this season in 96 games with the Royals while carrying a .717 OPS.
The eight-year MLB veteran has continued to be a strong producer against left-handed pitching, posting an .800 OPS against opposing southpaws this season.
Falter has struggled over just 9.2 innings on the year, allowing 15 earned runs. The 29-year-old southpaw did carry a 4.45 ERA over 26 appearances and 125.1 innings in 2025, splitting time between Pittsburgh and Kansas City.
He has been pitching in triple-A since May, where he has a 3.35 ERA and 46 strikeouts in 43 innings.
Both Thomas and Falter will become free agents at the end of the season.
Braun, a 24-year-old right-hander in triple-A with a 3.92 ERA, was Atlanta’s No. 8 prospect, per MLB Pipeline. And Holton, a 23-year-old southpaw in low-A, has a 4.32 ERA this season.
