Teixeira has been out with a lat strain after struggling at the plate. He had three hits in 24 at-bats before going down.
Tepesch has been rocked in recent outings. He has lost his last four decisions with 18 runs and 27 hits allowed in 22 2/3 innings.
The 35-year-old Guerrier had slumped after a strong run this season. He allowed five runs on 12 hits in his last seven innings before being designated for assignment.
Myers has been sidelined since May 30 with a wrist injury. He is not expected to rejoin his team until least mid-August.