The Astros placed Pena on the 10-day injured list Tuesday due to a mild left calf strain, Brian McTaggart of MLB.com reports.
Pena was held out of Monday's lineup due to leg discomfort, and manager Joe Espada said after the game that the shortstop would require an IL stint. Espada expressed optimism that it can be a minimum-length stay on the injured list, which would result in Pena rejoining the active roster July 10.