Quessenberry was placed on the NFL's Non-Football Illness list last season. He said Wednesday that he hopes to play in 2015.
"I'm back into it," Quessenberry said, according to ESPN.com. "We're training every day. We're enjoying this offseason time. I'm just using every day to get back to where I was before it happened. I know it's not going to take a week or a month, but hopefully in time I can get back to that point. ... Every day I feel myself getting stronger. Feel myself getting better."
The Texans selected Quessenberry in the sixth round of the 2013 draft out of San Jose State. He missed the entire 2013 season while recovering from a broken foot.