Tropeano had been on the disabled list since June 4 with tightness in his right shoulder. He is 3-2 in 10 starts for the Angels with a 3.25 ERA, the best among Los Angeles' starting pitchers.
After a season of injury problems for the Angels, they have six healthy starters after Tim Lincecum's addition to the big league roster last weekend.
Despite his solid performances this season, Tropeano is one of just three starters who can still be optioned without going on waivers.
Tropeano pitched five solid innings in a rehab appearance for Single-A Inland Empire on Thursday.