Two months after Robert Thomas was fighting for a job as a backup linebacker for the Cowboys, he'll make his first career start Sunday. He'll be playing fullback.

Thomas switched to offense during the final week of training camp, then got battle-tested quickly when an injury ended Daryl Johnston's season after the first game.

Although Tim Lester was signed in time to start the second game and every one since, Thomas played a great deal. He performed so well that Lester was cut this week, making Thomas the lead blocker for Emmitt Smith.

"I'm happy, but at the same time I know I have points to get better at," Thomas said. "Sometimes I have to be more graceful on offense than defense, but it's the same mentality--be aggressive and make sure you stay on your man."

The Cowboys use a fullback on only first and second downs, and not always on both. Sometimes a tight end will have fullback duties, and last Sunday Coach Chan Gailey experimented with RB Chris Warren in the backfield with Smith.

But in the little time the 255-pound Thomas has played, he has earned the confidence of coaches and future Hall of Fame players in the backfield, Smith and QB Troy Aikman.

"He's done a good job," Smith said. "He knows what to do."