ENGLEWOOD, Colo. -- The number in question is 16, as in 16 carries in three preseason games for running back Montee Ball.

From the time Ball took his first carry Aug. 14 in the Denver Broncos' preseason opener in Seattle to the 16th carry in Saturday's preseason game against San Francisco 49ers, Ball went from No. 2 on the team’s depth chart at running back to No. 4. And while a No. 4 running back usually makes the 53-man roster, he is often in street clothes for games as a game-day inactive.

Following Monday’s practice Ball was still sorting through the idea that what he expected in this preseason has not come to pass.

“I was [surprised]," Ball said. “I was expecting a lot more playing time. It caught me off guard, but my head’s not down. I'm going to keep it up and keep fighting."

Ball spent much of the offseason program as well as the early portion of training camp as the No. 2 back behind starter C.J. Anderson. At one point in June, Ball even professed the hope that, after his work in the offseason, he could make the battle close enough so he could be a "1-B" option behind Anderson as the "1-A."

But Ronnie Hillman kept romping to big gains in all three of the Broncos' preseason games -- a 7.4 yards per carry average -- and, for the first time in is career, began to appear in more and more special teams drills. Broncos coach Gary Kubiak has said "it's a must" the backup running backs have a presence on special teams.

Then, after eight carries in the preseason opener for just 26 yards, Ball got four carries in the second preseason game (for only 4 yards) and four carries Saturday night (for 11 yards). Against the 49ers, Ball was the fourth running back into the game for the first time in his career, having seen Juwan Thompson move ahead of him in the order.

Thompson can play both running back and fullback to go with his major role on special teams.

“It is tough because I feel like I really haven't had the opportunities in these preseason games, but there’s still one more [preseason game] left and I feel like I'll have some playing time in this one, and I'll show them what I can do," Ball said.

Ball, who was the team’s No. 1 back this time last year, is expected to play plenty in Thursday’s preseason finale against the Arizona Cardinals. Ball said Monday he’s hopeful the potential extra carries will help him find a groove in the new offense.

Ball is trying to make a final impression before the Broncos trim the roster to 53 players by Saturday. And he is auditioning as well if, for some reason, the Broncos elect to move on from their second-round pick in the 2013 draft.

“That's an important thing for a running back, to get that lather," Ball said. “To just figure out how the linebackers are flowing and stuff like that, but I'm not complaining at all. I'm not complaining.”

Ball played just 10 snaps against the Houston Texans in the second preseason game and 11 snaps Saturday night against the 49ers as Thompson got most of the work in the second half of the game, including a red zone carry that resulted in a 1-yard touchdown run with 2:04 left in the game. Broncos coach Gary Kubiak was asked after Saturday’s game about Ball’s slide down the depth chart.

“I think [Thompson] ... got all of the late caries in the game," Kubiak said. “There's nothing Montee's done. It's hard to get four guys carries in a game. He continues to work hard. Special teams is a big factor with him and Juwan as far as playing on a regular basis. We'll see. I'm fine with Montee. I wish there would be more [total carries]. I promise you they'll probably be plenty to go around on Thursday."

Ball played in just five games last season because of a groin injury he suffered in Week 5 against the Arizona Cardinals. Ball tried to play six games later (Nov. 9 against the St. Louis Rams), but was not ready to play and finished the season on injured reserve.