Johnson caught 731 career passes for 11,619 yards and 83 touchdowns.
"It's my decision," Johnson said. "I made my own decision. I'm good with it."
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"I wouldn't just quit because we were losing," Johnson said. "Just [my] body, man, I was tired of it. I was fed up. Had enough. I'm not coming back. You ain't gotta worry about that."
Johnson knew he would retire before last season.Aaron Wilson covers the Texans for The Houston Chronicle.