Adams, 24, has gone 13 for 24 (.542) with three doubles and three home runs as a part-time player this season. Aside from Adams' occasional spot start at first, manager Mike Matheny typically uses him as his primary left-handed pinch-hitter off the bench.
Adams missed about three weeks with an oblique strain while in the minor leagues back in 2011. He had surgery to remove bone chips from his right elbow last August.
Curtis, 25, is hitting .292/.386/.458 with one homer and two steals in 17 games for St. Louis' Triple-A affiliate this year. He has experience at second base, third base and left field. Curtis has never appeared in the big leagues.