"I think the more motivation I get the better I run the football."

Karlos Williams' motivation on Friday night was the opportunity to handle first and second team running back duties in the Bills 25-24 loss to the Carolina Panthers. With injuries to Fred Jackson and Boobie Dixon, Williams came in behind LeSean McCoy and he did not disappoint; he tallied 40 rushing yards with two receptions for 23 yards. 

"You've just got to take advantage of it," Williams said of his opportunity. "I'm just trying to carry the load and do what I have to do to make sure I make this roster."

Williams first saw the field in the middle of the first quarter and had two carries for 13 yards on a drive that set up a 37-yard field goal attempt. He totaled 11 yards on the Bills next offensive drive, capping it off with a one-yard touchdown dive.

"[I'm] just happy to stick it in the end zone," he said. "[I] didn't know if I wanted to dive, didn't know if I wanted to walk it in. Kind of a half-way dive and coach is definitely going to get on me about that one."

Williams attributed some of his success in his first NFL game to the offensive line. In total, the line pushed forward for 206 yards on the ground, compared to just 73 for the Panthers.

"The offensive line did a great job moving the ball up and down the field," Williams said. "Being able to run the ball like that is amazing and I'm just happy to be a part of it."

As a rookie, there are still adjustments to be made for Williams. The difference between college and professional football is stark and Williams noticed that on Friday.

"The NFL is fast. It's a lot different from college to the NFL," he said. "I was telling some teammates, some veterans that and they kind of laughed and said, 'You know it's only going to get faster during the regular season.'"

Williams has the benefit of playing with four seasoned veterans at the running back position. The four backs with NFL experience on the Bills roster have a combined 14,332 career rushing yards with 90 touchdowns on the ground.

"You've just got to … keep learning from Fred [Jackson] and Boobie [Dixon] and LeSean [McCoy] and Bryce [Brown] and just keep pushing forward week in and week out until the regular season comes around," Williams said.

Williams' performance caught the eye of quarterback Matt Cassel. Cassel said that Williams had "an eagerness about him" and that he made the most of his opportunity on Friday.

"I remember just before we even went out and he was excited," Cassel said. "He said his dream is coming true, it was his first time stepping on the field."

Head coach Rex Ryan was also impressed with Williams' performance on Friday, emphasizing that it reflected his play during practice.

"This is what he's been showing during training camp," Ryan said. "He ran hard and he does a good job in protection and he caught the ball decent. We've seen these types of things [from him], but he just keeps getting better and better."

Williams is in the middle of what will be an intense position battle through the last two weeks of training camp. According to McCoy, the surplus of talent could lead to good things and although no roster spots are guaranteed, Williams showed that he could make a difference come September.

"That's actually good, to have a good depth chart in the backfield," McCoy said. "We play a very tough position and guys always get banged up."

"Hopefully I earn myself a roster spot on special teams and try and work my way into getting carries," Williams said. "[I'm] going to go home, watch the film, get back to practice next week and get on the film and learn from this experience and just keep pushing forward, keep trying to get better."