Houston selected Clowney out of South Carolina to form a powerful 1-2 pass-rushing attack with J.J. Watt.
Baker left on a cart in the second quarter with a right knee injury, a potentially huge blow to the Falcons' reshaped offensive line.
Baker started 16 games in 2012, but played in just four games last season because of a left knee injury that required surgery in November.
Ryan went 3 for 7 in a quarter and a half of work and Julio Jones caught two passes in his first live-game action since he broke his right foot in Week 5 last season.
A Falcons' penalty moved the ball to the Atlanta 8, and Fitzpatrick avoided the rush to his right before finding Posey in the back of the end zone with 19 seconds left.
Houston's special teams and defense took over from there.
Yates played the fourth quarter under constant pressure, and tried a futile tackle attempt on Hal's return. Matt Bullough also intercepted Yates, setting up a 33-yard field goal by Chris Boswell.
Copyright 2014 by The Associated Press