Miami Dolphins quarterback Ryan Tannehill (17) warms up before a preseason NFL football game against the Dallas Cowboys, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Miami Dolphins quarterbacks Matt Moore (8) and Ryan Tannehill (17) warm up before a preseason NFL football game against the Dallas Cowboys, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Dallas Cowboys quarterback Stephen McGee (7) looks to hand the ball off as running back Shaun Chapas (45) runs by during the first half of a preseason NFL football game against the Miami Dolphins, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Dallas Cowboys tackle Jeff Adams (70) and linebacker Victor Butler (57) tackle Miami Dolphins running back Daniel Thomas (33) during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Miami Dolphins quarterback Ryan Tannehill (17) passes against the Dallas Cowboys during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Dallas Cowboys quarterback Stephen McGee (7) passes against the Miami Dolphins during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Tony Gutierrez)

Dallas Cowboys quarterback Stephen McGee (7) passes against the Miami Dolphins during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Tony Gutierrez)

Miami Dolphins defenders Paul Soliai (96) and Austin Spitler tackle Dallas Cowboys' Phillip Tanner (34) during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Tony Gutierrez)

Miami Dolphins defensive tackle Kheeston Randall (97), defensive end Olivier Vernon (50), and linebacker Jamaal Westerman (52) take down Dallas Cowboys quarterback Stephen McGee (7) during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Miami Dolphins running back Charles Clay (42) makes a reception as Dallas Cowboys linebacker Orie Lemon (58) defends during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Miami Dolphins running back Charles Clay (42) makes a reception as Dallas Cowboys linebacker Orie Lemon (58) defends during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Dallas Cowboys tackle Jeff Adams (70) and linebacker Orie Lemon (58) tackle Miami Dolphins running back Daniel Thomas (33) during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Dallas Cowboys cornerback Teddy Williams tackles Miami Dolphins wide receiver Legedu Naanee (19) during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Tony Gutierrez)

Miami Dolphins punter Brandon Fields holds for kicker Dan Carpenter (5) as he makes a field goal against the Dallas Cowboys during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Dallas Cowboys quarterback Stephen McGee (7) hands the ball to Lance Dunbar (25) during the first half of a preseason NFL football game against the Miami Dolphins, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Tony Gutierrez)

Miami Dolphins wide receiver Marlon Moore (14) forces Dallas Cowboys cornerback Teddy Williams (20) to fumble the ball during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Dallas Cowboys cornerback Teddy Williams (20) breaks up a pass to Miami Dolphins wide receiver Legedu Naanee (19) during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas (AP Photo/Tony Gutierrez)

Dallas Cowboys' Eddie Whitley, left, tackles Miami Dolphins running back Marcus Thigpen during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Dallas Cowboys running back Phillip Tanner (34) takes the ball down field against the Miami Dolphins during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Dallas Cowboys punter Chris Jones (6) holds as kicker Dan Bailey (5) makes a field goal against the Miami Dolphins during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Dallas Cowboys linebacker Orie Lemon (58) scores a touchdown off an interception thrown by Miami Dolphins quarterback Matt Moore during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Miami Dolphins defensive back Nolan Carroll (28) breaks up a pass to Dallas Cowboys wide receiver Dwayne Harris (17) during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Dallas Cowboys wide receiver Kevin Ogletree (85) misses a reception as Miami Dolphins defensive back Quinten Lawrence (36) defends during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Dallas Cowboys linebacker Orie Lemon (58) scores a touchdown off an interception thrown by Miami Dolphins quarterback Matt Moore during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Miami Dolphins running back Steve Slaton (23) defends against Dallas Cowboys wide receiver Tim Benford (16) during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Dallas Cowboys running back Phillip Tanner gets up from the field after scoring a touchdown against the Miami Dolphins during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Miami Dolphins quarterback Matt Moore (8) passes against the Dallas Cowboys defense during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Miami Dolphins defensive end Ryan Baker (90) misses tackling Dallas Cowboys quarterback Stephen McGee (7) during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Miami Dolphins quarterback Matt Moore (8) is sacked by Dallas Cowboys linebacker Alex Albright (55) during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Dallas Cowboys linebacker Orie Lemon (58) celebrates after scoring a touchdown from an interception thrown by Miami Dolphins quarterback Matt Moore with Cowboys defensive back Mario Butler, left, during the first half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Miami Dolphins wide receiver B.J. Cunningham (16) is tackled by Dallas Cowboys cornerback Teddy Williams (20) during the second half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Miami Dolphins running back Lamar Miller (44) is tackled by Dallas Cowboys safety Eddie Whitley (38) and defensive tackle Rob Callaway (72) during the second half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Miami Dolphins running back Lamar Miller (44) is tackled by Dallas Cowboys' Eddie Whitley (38) during the second half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Miami Dolphins quarterback Matt Moore (8) is sacked by Dallas Cowboys tackle Jeff Adams (70) during the second half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Dallas Cowboys running back Lance Dunbar (25) is tackled by Miami Dolphins cornerback Vince Agnew (43) and defensive tackle Kheeston Randall (97) during the second half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Miami Dolphins linebacker Shelly Lyons (48) tackles Dallas Cowboys running back Jamize Olawale (49) during the second half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Aug 29, 2012; Arlington, TX, USA; Miami Dolphins wide receiver Marlon Moore (14) is tackled by Dallas Cowboys linebacker Baraka Atkins (59) during the second quarter at Cowboys Stadium. Mandatory Credit: Tim Heitman-US PRESSWIRE

Aug 29, 2012; Arlington, TX, USA; Dallas Cowboys running back Phillip Tanner (34) scores a touchdown during the second quarter against the Miami Dolphins at Cowboys Stadium. Mandatory Credit: Tim Heitman-US PRESSWIRE

Aug 29, 2012; Arlington, TX, USA; Miami Dolphins cornerback Nolan Carroll (28) defends a pass against Dallas Cowboys wide receiver Dwayne Harris (17) during the second quarter at Cowboys Stadium. Mandatory Credit: Tim Heitman-US PRESSWIRE

Aug 29, 2012; Arlington, TX, USA; Miami Dolphins quarterback Ryan Tannehill (17) calls a play on the line of scrimmage during the first quarter of the game against the Dallas Cowboys at Cowboys Stadium. Mandatory Credit: Tim Heitman-US PRESSWIRE

Dallas Cowboys quarterback Rudy Carpenter (11) is tackled by Miami Dolphins defensive tackle Kheeston Randall (97) during the second half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/LM Otero)

Dallas Cowboys quarterback Rudy Carpenter (11) passes the ball against the Miami Dolphins during the second half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Dallas Cowboys quarterback Rudy Carpenter (11) is tackled by Miami Dolphins defensive tackle Kheeston Randall (97) during the second half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Dallas Cowboys running back Lance Dunbar runs the ball against the Miami Dolphins defense during the second half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Dallas Cowboys quarterback Rudy Carpenter (11) hands the ball to running back Lance Dunbar (25) during the second half of a preseason NFL football game against the Miami Dolphins, Wednesday, Aug. 29, 2012, in Arlington, Texas. (AP Photo/Sharon Ellman)

Miami Dolphins quarterback Matt Moore (8) leaves the field after a preseason NFL football game against the Dallas Cowboys, Wednesday, Aug. 29, 2012, in Arlington, Texas. The Cowboys won 30-13. (AP Photo/LM Otero)

Miami Dolphins tight end Jeron Mastrud (88) tangles with Dallas Cowboys linebacker Victor Butler (57) as the ball pops loose after a touchdown scored by Dolphins' Lamar Miller (not shown) during the third quarter of the NFL preseason football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. The Cowboys won 30-13. (AP Photo/LM Otero)

Miami Dolphins quarterback Ryan Tannehill (17) and Dallas Cowboys quarterback Stephen McGee (7) talk after a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. The Cowboys won 30-13. (AP Photo/LM Otero)

Miami Dolphins cornerback Vince Agnew (43) tries to tackle Dallas Cowboys running back Jamize Olawale (49) during the second half of a preseason NFL football game, Wednesday, Aug. 29, 2012, in Arlington, Texas. The Cowboys won 30-13. (AP Photo/Sharon Ellman)

Dallas Cowboys running back Lance Dunbar, left, and team mascot Rowdy bump fists after a preseason NFL football game against the Miami Dolphins, Wednesday, Aug. 29, 2012, in Arlington, Texas. The Cowboys won 30-13. (AP Photo/Sharon Ellman)

Dallas Cowboys head coach Jason Garrett leaves the field after a preseason NFL football game against the Miami Dolphins, Wednesday, Aug. 29, 2012, in Arlington, Texas. The Cowboys won 30-13. (AP Photo/Sharon Ellman)