MIAMI (AP) – Larry Johnson scored on a 22-yard touchdown run and Matt Moore threw for another score Thursday night to help the Miami Dolphins win a battle of backups by beating the Dallas Cowboys 17-3 in the final exhibition game for both teams.

Reluctant to risk injuries so close to the start of the regular season, the Cowboys designated 31 of their 80 players as inactive, while the Dolphins had 21 inactive players. Three starters were active for each team.

Johnson, a two-time Pro Bowl selection who signed with the Dolphins last week after sitting out most of last season, rushed for 39 yards on 10 carries and scored the game’s first points.

123311514 81 Dolphins Flatten Cowboys In Final Preseason Game

Cowboys vs Dolphins Photos

Moore, another Miami newcomer, went 9 for 11 for 142 yards, including an 18-yard touchdown pass to third-string tight end Jeron Mastrud.

Dallas third-string quarterback Stephen McGee went 21 for 25 for 233 yards but couldn’t get his team into the end zone. The Cowboys’ only points came on a 20-yard field goal by David Buehler, who is battling to keep his job.

Running back DeMarco Murray, competing for the backup spot behind Felix Jones, carried 10 times for 32 yards.

The only Dolphins starters active were receiver Brian Hartline, linebacker Koa Misi and safety Chris Clemons. Cowboys active starters were fullback Chris Gronkowski, top draft pick Tyron Smith and rookie guard Bill Nagy.

With roster cuts looming this weekend, about half the players who saw action will likely be released.

Dallas (2-2) will play its regular-season opener Sept. 11 against the New York Jets. Miami (3-1) opens the following night against New England.

Moore, slated to back up Chad Henne this season, started the game and led touchdown drives of 79 and 59 yards. His completions included a deep pass to speedy rookie Clyde Gates for a 42-yard gain that set up a TD.

Dan Carpenter kicked a 50-yard field goal for Miami.

On the Cowboys’ first play, Murray took a short pass from McGee and turned it into a 48-yard gain. McGee later led Dallas on a 17-play drive that took nearly 9 minutes and ended with Buehler’s field goal.

Cowboys Owner/CEO Jerry Jones on 105.3 The Fan

Notes: Miami veteran Will Allen, battling for a roster spot, leaped to break up a pass in the end zone that was intercepted by Tyrone Culver. … The Dolphins committed only two penalties for 15 yards. … The small crowd included at least one celebrity: singer Cee Lo Green.

(Copyright 2011 by The Associated Press. All Rights Reserved.)