The Athletics selected Kuhnel's contract from Triple-A Las Vegas on Tuesday.
The right-hander delivered two scoreless outings for Las Vegas and will replace Luis Morales on the Athletics' active roster. Kuhnel last pitched in the majors in 2024, when he made 10 regular-season appearances between the Rays and Astros and gave up five earned runs with a 5:0 K:BB over 10 innings.