Calhoun (hamstring) was activated off the injured list and will start Friday against Houston, batting fifth and serving as the designated hitter.
Calhoun missed over a month with a hamstring strain but is ready to go after appearing in just a single official rehab game. He's hit an unremarkable .238/.293/.354 in 140 plate appearances this season and is a 33-year-old on an expiring contract (assuming the Diamondbacks don't pick up his option), so he could find himself sitting regularly as the team tries out younger players down the stretch.