TULSA, Okla. � With a logjam in Boise State�s backfield, Doug Martin had become expendable.

There were too many backs and not enough carries, and he ended up getting groomed into a new role on defense this season.
An injury and an illness later, he�s once again an essential part of the Broncos� offense.
When D.J. Harper suffered a left knee injury in Boise State�s third game of the season, coach Chris Petersen made the move to bring Martin back to the offense in what would be a bittersweet switch.
�It was real unfortunate that D.J. went down,� said Martin, a sophomore from Stockton, Calif. �We�re real good buddies. We�ve been buddies since I first got here.
�I�m just carrying the flag for him. It�s been a really nice experience, and I�m just going to keep doing it for him.�
Martin surpassed 100 yards rushing for the second time in three games when he ran for 112 in the Broncos� 28-21 win Wednesday night at Tulsa.
With Boise State (6-0) up only 15-14 at halftime, Petersen turned to Martin to carry the load in the second half. Martin got the ball 12 times on the Broncos� first two drives of the third quarter, and he made the most of it.
Martin ran around and through Tulsa�s defense for 83 of his team�s 104 yards rushing in the third quarter as Boise State scored the period�s only 10 points. Petersen said he relied on Martin even more because starter Jeremy Avery was �under the weather.�
�He�s kind of a power runner and he�ll break tackles and he�ll slam it up in there,� Petersen said. �I think he and Jeremy are a good 1-2 punch.�
Martin had only 24 carries for 107 yards all of last season, but he made a mark elsewhere. He earned the �Hammer� award as the most physical special teams player on the team, then shifted to defense during spring practice.
He�s slowly been taking on a bigger load since moving back to offense, getting 13 carries against Bowling Green and then 16 against UC Davis.
Martin carried the ball a career-high 23 times against Tulsa and was called on five straight times to start Boise State�s second drive after halftime. He racked up 42 yards and also drew a 15-yard facemask penalty as he moved the Broncos into field goal range.
�It�s a lot better. Last year, when I shared with (Ian Johnson) and D.J., it was like we couldn�t get a rhythm,� said Martin, who had a career-best 116 yards against Bowling Green. �I think it was a lot better getting play after play after play, getting the feel, getting the rhythm, the speed of the defense and just the speed of the game in general. I think it was a lot better that way.�
Behind Martin�s running, the Broncos were able to take control of the game and build a big enough lead that Tulsa (4-2) couldn�t come back.
�The difference probably in the game was their ability to run the football, and they didn�t do it by lining up and just running right at us,� Tulsa coach Todd Graham said. �They did a lot of movement and things like that, and they�re very, very well coached and do a great job of displacing you on defense.�
Avery complemented Martin with 16 carries for 73 yards as the Broncos ran for 193 yards � just over the 191.6 yards they had been averaging.
�Doug�s a good player. He�s a hard-nosed player and fortunately for us, losing a guy like D.J. Harper, Doug is a similar type back to him,� Petersen said. �He�s a strong, tough runner and we were crushed when we lost D.J. But on a positive note, we really felt like Doug could pick up the baton and we wouldn�t miss a beat, and he�s a heck of a running back.�