ANAHEIM -- Rangers outfielder Nomar Mazara left Friday night's 7-6 loss to the Angels still experiencing tightness in his left quad muscle, a problem that has been bothering him for over a week.

It is one of a number of signs the Rangers may be running out of gas as they go down the stretch and start to fade in the American League Wild Card race. The loss was the Rangers' seventh in the last nine games and they are five games behind the Twins for the second spot with 15 to play. The Angels, Mariners and Royals are between them and the Twins.

"We are not happy about it, the whole clubhouse," outfielder Shin-Soo Choo said. "We still have 15 games left, there is a lot of drama in sports. We believe that could happen, we'll still keep playing. Nobody is giving up ... it was just a tough loss."

This was Mazara's first game in the outfield since Sunday against the Yankees. He was used at designated hitter in three of four games against the Mariners, but did not start on Thursday. Mazara said he could have finished the game, but the Rangers had taken a 4-2 lead in the top of the sixth so manager Jeff Banister decided to upgrade his defense by putting Drew Robinson in left.

"Nomar has been battling quad issues the past couple of weeks," Banister said. "It was a situation where he had made the last out in the inning and we felt it was more important to play defense the next few innings ... give us a fresh set of legs."

The designated-hitter spot is not an option at the moment because the Rangers need that spot to get Adrian Beltre (strained left hamstring) in the lineup. Mike Napoli, dealing with a stress reaction in his right leg, is next in line there. Carlos Gomez is still out with a sprained right ankle and Rougned Odor , hitting .143 in his last 24 games, is dealing with an ankle issue. The Rangers went to check on him during a third inning at-bat.

"Nobody is playing healthy, nobody is 100 percent this time of year," Choo said. "Everybody is playing with something. You just have to keep playing."

Choo hit a two-run home run in the sixth to give the Rangers a 4-2 lead. But the Angels struck back with five runs in the bottom of the inning against starter Nick Martinez and rookie relievers Yohander Mendez and Ricardo Rodriguez .

"I don't know if we are running out of gas but we have some guys out there with lower leg injuries and it may look that way," Banister said. "We are not able to do as much as we'd like to do but they are still playing with a lot of energy. Even when we have up five runs in the sixth, guys were still playing hard."