Texas designated catcher Sam Huff for assignment to make room for Armstrong on the 40-man roster.
Armstrong is coming off a season playing for three different teams (Tampa Bay Rays, St. Louis Cardinals, and Chicago Cubs). He had a 4.86 ERA for the year in 57 games, giving up 77 hits and 25 walks in 66.2 innings with 66 strikeouts. His 1.909 WHIP last season set a career-high.
The Rangers will now make it eight teams for Armstrong in 10 years. His breakout year was in 2023 in which he threw a stellar 1.38 ERA in 39 appearances, giving up 36 hits and 11 walks while striking out 54 batters in 52 innings.
Armstrong will be joining a Rangers team that ranked 24th in team ERA, 17th in hits, and 15th in strikeouts last year.
Texas finished the 2024 season with a 78-84 record, missing the playoffs one year removed from winning the 2023 World Series.