The Bills released Schobel on Aug. 4 after nine seasons. Schobel was a two-time Pro Bowl selection and his 78 career sacks rank second in Buffalo history behind Hall of Famer Bruce Smith.
Schobel mulled his options for two weeks, and his decision to retire on Monday was first reported by FoxSportsHouston.com. He said in a phone interview with The Associated Press that he had been leaning toward retirement since the end of last season.
"I really didn't have a lot of fun playing last year," Schobel said. "The passion wasn't there, so it was time. I took as much time as I felt like I needed to make the decision, and I think I made the right one."
Schobel, 32, lives in Columbus, Texas, about 70 miles west of Houston, and the Texans contacted Schobel about continuing his career close to home this season.
Another lure to Houston was defensive line coach Bill Kollar, who worked in Buffalo for three seasons before joining the Texans in 2009. The two are close friends, but Schobel felt retiring was still the right decision to make.
"The decision came down to whether I wanted to play," he said. "I didn't really feel like I wanted to do it. A lot of people probably think I'm crazy, but whenever you feel like it's time, it's time."
Schobel had four years left on a $50.5 million contract extension he signed with the Bills in 2007. It's a deal that included a $2 million roster bonus he was due March 1. Schobel did not receive that money, because the payment was due on the condition he passed a physical.
"It's always hard to pass up money, but there's more to life than that," Schobel said. "If I wanted to play, I felt like I still could've. But it was time."
Schobel sold his house near Buffalo in the spring. He has three children, and said the annual move from Texas to New York was starting to wear on them.
"My kids are getting older and I didn't feel like it was fair," he said. "It was getting to the point where it was starting to affect them, so that was the reason not to go back to Buffalo."
Schobel did not participate in any team activities this offseason. He was placed on the Reserve/Did Not Report list when he failed to show up for the start of training camp.
Aside from considering his family, Schobel said he was unsure if his body could hold up for another season.
"It wasn't just the physical part, but the mental part, too," he said. "After the Bills released me, I weighed all my options and I just decided that at this point, this is what I wanted to do. I was tired of going back and forth. I just decided that this is what I was going to do."
The Texans were hoping to build depth on their defensive line after backup end Tim Bulman sustained a shoulder injury that coach Gary Kubiak says will sideline him for several weeks.
"We have to continue on with what we're doing," Kubiak said. "I wish [Schobel] the best. He's a good person and a good player."
Houston placed Bulman on injured reserve Monday and signed free-agent James Wyche, one of three defensive ends who worked out for the team last week.
Kollar said he talked to Schobel "quite a few times" about playing in Houston, but never got a clear read on how much Schobel considered coming back for another season.
"I know he was really considering it," Kollar said. "I don't know what turned out to be the deciding factor. He had mentioned that his family, that they kind of wanted to settle down and stay in one place."