Tony Romo, not fully recovered from his broken collarbone injury, started the next game against the Dolphins, which they won.
However, in a week 12 loss against the undefeated Panthers, Romo suffered a second collarbone injury and was later ruled out for the season.
However, after a poor performance against the New York Jets in week 15 in the 1st half, Cassel was benched in favor of backup Kellen Moore, and the team went on to lose the rest of the games of the season.
The Cowboys opened the season at home against their rival, the New York Giants, led by the quarterback-receiver tandem of Eli Manning and young Odell Beckham Jr. Tony Romo came back late in the fourth quarter and nailed the game-winning drive to Jason Witten to give Dallas a narrow 27-26 victory.
Shining atop the division, the Cowboys played their divisional rivals, the Philadelphia Eagles in what turned out to be a defensive juggernaut of a game.
Already missing starting wide receiver Dez Bryant, the Cowboys experienced a devastating loss when Tony Romo was sacked by Jordan Hicks.
Backup Brandon Weeden got his first taste of game time this season, completing all of his 7 passes for a total of 73 yards and one touchdown.
Despite the injuries to the two key players, the Cowboys still managed to hold off the Eagles with a 20-10 victory, ultimately stunning Philadelphia's home crowd.
Many questions surrounded the Dallas Cowboys as they entered Week 3, especially regarding how the team would respond to having neither Dez Bryant nor Tony Romo.
Coach Jason Garrett's mantra of “next man up” played a big part in preparing for the game against the Atlanta Falcons.
Backup quarterback Brandon Weeden started for the first time since the previous season's game against the Arizona Cardinals, completing 22 of 26 passes for 232 yards and one interception with no touchdowns.
In another heartbreaking loss which ended a 9-0 winning streak of regular season away games, the injury bug struck the Cowboys again.
Sean Lee exited the game early with a concussion, Lance Dunbar saw the last of his playing time this season with a torn ACL, and Brice Butler injured his hamstring.
Enduring a few lead changes throughout the first four quarters, the Cowboys were able to come back and tie it up 20-20 with a last minute touchdown from Brandon Weeden (16/26; 246 yards; 1 TD) to Terrance Williams.
After back-to-back losses, Dallas returned home to face the then-undefeated defending Super Bowl champions, the New England Patriots.
Stout early defensive efforts kept the game close, including five sacks of Patriots quarterback Tom Brady, but Dallas's offense could never produce steady results.
On the ground Dallas had consistent success all day with Darren McFadden substituting for mysteriously injured starter Joseph Randle and the offense accumulated 460 total yards vs. the Giants' 289.
Despite sloppy, penalty-ridden play helping enable three lead changes Dallas was able to tie the game at 20 when Cassel threw a beauty on a 25-yard touchdown pass to Devin Street who had an even better catch, tapping his feet inches from the end line.
The loss hands Dallas a four-game losing skid heading back home to face the defending NFC champion Seattle Seahawks.
This game involved a scary moment, after Seattle's Ricardo Lockette was hit by Dallas's Jeff Heath during a kick return.
The Cowboys would rally to tie the game after Dan Bailey converted a 44 yard field goal that caromed off the uprights with 2 seconds left.
Washington would score soon afterwards, with DeSean Jackson catching a 28-yard touchdown pass from Kirk Cousins to tie the game at 16.
With the win, the Cowboys improved to 4-8 and remained in the playoff hunt, aided by the fact that all four NFC East teams had losing records.
Towards the end of the game, Jets quarterback Ryan Fitzpatrick would sneak the ball across for a first down deep in his own territory.
The Cowboys would trail 0-24 by the second quarter, and despite an attempt to come back, they would go on to lose 23-34 to the NFC East Champions Redskins.