The Rangers placed Montgomery (elbow) on the 60-day injured list Sunday.
The transaction frees up a spot on the 40-man roster for outfielder Dairon Blanco, whom the Rangers claimed off waivers from the Royals. The move to the 60-day IL won't affect Montgomery's return timeline, as the veteran southpaw was already expected to miss multiple months as he continues his recovery from hybrid UCL reconstruction surgery, which he underwent last April.