HOUSTON -- A daily review of the hot topics coming out of Houston Texans training camp.

• Red zone work was an emphasis during Friday morning's practice to middling results. "The red area is totally different than out in the field," coach Bill O'Brien said. "The windows are tighter, they close faster, they open fast and they close fast, there is less area to defend, so the DBs are able to take more chances, there is more specialized coverage down there so you are able to see, 'Hey look, they're doing this that they don't do out in the field, but they're doing this in the red area.' We've got to be ready for that type of coverage."

• After coming off the non-football injury list, running back Jonathan Grimes saw immediate action. He made a nice catch on a short pass from quarterback Ryan Fitzpatrick. "It was awesome to get back in there, get my legs back and everything, and be able to work,” Grimes said.

• Receiver Joe Adams was such a dynamic player in college, but had some fumbling issues in the NFL that eventually led to his winding up with the Edmonton Eskimos of the CFL. Adams didn't do too much in his first practice, but he stayed clean with what he did. I'm looking forward to watching him as camp progresses. You should have seen the smile on his face when I asked what it feels like to make a game-changing return.

• Defensive coordinator Romeo Crennel is having all the safeties learn sides, rather than specialize in free or strong safety. "As we start game planning, then we might make a guy our down safety and a guy a deep safety. But they're both left and right safeties and both have to learn strong and free." That's a departure from former defensive coordinator Wade Phillips. Danieal Manning was a guy who could play either, but that wasn't the case with everyone. D.J. Swearinger stayed off the field until there was an opening at strong safety.

• The Texans practice from 8 to 10:30 a.m. Saturday and the practice is open to the public. Their walkthrough in the afternoon is closed.