Undrafted free agent quarterback Bart Houston threw a 6-yard touchdown pass to Justin Hunter with 6:35 remaining in the fourth quarter to give the Pittsburgh Steelers a 17-13 victory against the Atlanta Falcons on Sunday at Heinz Field in Pittsburgh.

The Steelers scored 14 unanswered points in the second half after falling behind 13-3 at halftime. Trey Williams scored on a 64-yard punt return in the third quarter for the Steelers other touchdown.

The comeback victory wasn't all rosy for the Steelers. The Falcons scored on their first three possessions and racked up 259 yards in the first half with most of it coming against the Steelers' first-team defense.

Atlanta quarterback Matt Ryan played one series and led the Falcons on a 91-yard touchdown drive to open the game. He was 4 for 6 for 46 yards on the drive, including an 18-yard connection to Marvin Hall that set up Terron Ward's 5-yard touchdown run.

The Falcons did not play star receiver Julio Jones or running back Devonta Freeman, but their replacements had no problem finding holes in the Steelers' defense, even after third-string quarterback Matt Simms took over for the remainder of the first half.

Simms directed two consecutive field-goal drives after Ryan was taken out of the game. He was 11 for 19 for 157 yards in the first half, working against a Steelers' defense that played its healthy starters for most of the first half.

The Steelers were missing three starters on defense -- safety Mike Mitchell, inside linebacker Ryan Shazier and outside linebacker Bud Dupree. Of the 259 first-half yards the Steelers allowed, 211 were passing yards. The starters on the Steelers' defense played all but the final two minutes of the half.

The Steelers offense played without quarterback Ben Roethlisberger, receiver Antonio Brown and running back Le'Veon Bell, who has yet to report to training camp or sign his one-year franchise player tender. Backup quarterback Landry Jones also sat out with an injury, leaving rookie Josh Dobbs to start his second consecutive preseason game.

Dobbs was 10 for 19 for 70 yards and an interception. He led the Steelers to one scoring drive, which was capped off by a 42-yard field goal by Chris Boswell.

Reserve safety Jordan Dangerfield had two second-half interceptions to lead the Steelers' defense.