Batch, 37, has thrown just two passes in a game this season and has appeared in seven games -- two starts -- over the last three seasons.
Roethlisberger has been hampered since sustaining a high ankle strain Dec. 8. He played Monday, throwing three interceptions in a 20-3 loss at San Francisco.
However, the Steelers have already locked up a playoff spot, giving Steelers Coach Mike Tomlin the opportunity to rest Roethlisberger when the 2-12 St. Louis Rams play at Pittsburgh Saturday.
Pittsburgh and Baltimore are tied at 10-4 for the lead in the AFC North.