Ramirez, 34, battled a left knee problem in spring training and aggravated it while running the bases on Friday. He acknowledged playing through some lingering soreness after the game. An MRI on Saturday confirmed the injury.
The Brewers are already without Corey Hart (knee) and Ryan Braun (neck), so losing Ramirez is a huge blow to the offense. He had gone 5 for 13 (.385) with three doubles in four games before the injury. Rickie Weeks and Alex Gonzalez will bat 3-4 against the Diamondbacks on Saturday.
Prince, 25, hit .251/.346/.360 with seven homers in 137 Double-A games last summer. He played in two games with the club's Triple-A affiliate before being recalled. Prince has never appeared in a big league game.