Financial terms of the deals were not immediately available, but rookies selected after the first two rounds typically sign four-year deals.
Granson was a fourth-round pick, No. 127, overall out of SMU. Ehlinger was taken in the sixth round, No. 218, out of Texas.
The announcement comes as the Colts near the end of their first week of light, voluntary workouts at the team complex. Indy announced it had signed its other five draftees on May 6.
The Colts believe the 6-foot-3, 235-pound Granson can help stretch the field and will be an elusive runner after the catch. They hope he can also emerge as a solid blocker.
Ehlinger is expected to compete for the backup job with Jacob Eason, Indy’s fourth-round pick last season. The Colts also acquired starting quarterback Carson Wentz in a trade with Philadelphia. Wentz will replace the retired Philip Rivers.
Ehlinger left the Colts rookie camp when his younger brother, Jake, was found dead near the Texas campus.