Martinez was placed on the seven-day disabled list, which is new this year for players with concussions. He was played on the DL on June 9.
"He's still doing some tests," Astros manager Brad Mills said. "They want to run him through some drills on the field today, looking up at the lights and looking around to see how he's feeling. If that goes well, he's going to run through some concussion test to see how he's doing. Once he does that, we'll run him through more hitting drills and send him out on rehab."
Martinez, claimed off waivers from the Mets in the offseason, was hitting .319 with eight homers and 38 RBIs when the Astros called him up earlier this month. He appeared in only four games for Houston before going on the DL, notching one hit in 15 at-bats with nine strikeouts.