ENGLEWOOD, Colo. (AP) -- Between Peyton Manning and Willis McGahee, the Broncos have a quarter century of experience in their starting backfield. Rookie running back Ronnie Hillman, the NFL's youngest player, is barely old enough to buy his teammates a drink.
Hillman, who will be 21 years, 1 month, 21 days old when Denver plays at Cincinnati on Sunday, is soaking up knowledge from the veterans on a daily basis. As the lessons sink in, it's not surprising his role with the Broncos is expanding, as well.
Last week against the Saints, Hillman had his biggest day. Spelling the man who has become his mentor, McGahee, the Broncos rookie was on the field for 27 plays, carried the ball on 14 of them and gained 86 yards.
"He's a young player who's getting better every week," Broncos offensive coordinator Mike McCoy said. "He's fortunate to watch Willis every day. He's got a good role model."
The Broncos (4-3) have been taking it slow with their rookie third-round draft pick, as he learns the subtleties of NFL blocking schemes and gets used to the grind of playing a longer schedule in a league that's, well, slightly more physical than what he went against during his two seasons at San Diego State.
Like most rookie running backs, Hillman has gone through his share of growing pains as he figures out how to protect the two most important things on the field -- the ball and the quarterback. Those issues, plus a hamstring injury that cost him playing time in the preseason, relegated him to the inactive list the first two weeks and held him to a total of 17 carries in his first four games on the active roster, seven of which came in the second half of a blowout win over Oakland.
Slowly, though, he is finding his way onto the field -- his time there directly related to his ability to understand the blocking schemes.
"I'm pretty sure of it. They just want to get more comfortable with me in there in case a team decides to blitz," Hillman said.
Over the past month, Hillman has vaulted up the depth chart from the Broncos' fourth running back to No. 2, leapfrogging Lance Ball and 2009 first-round draft pick Knowshon Moreno, who lost a fumble in Week 2 against Atlanta and hasn't been on the active roster since.
At 5-foot-10, 190 pounds, Hillman has more flat-out speed and elusiveness than McGahee. McCoy said he doesn't use the backup so much as a "change of pace guy," as an option for when McGahee needs a rest. Unspoken in all this is that the Broncos are ramping things up for Hillman at the midseason point -- a point at which a 31-year-old back such as McGahee, second-oldest starting running back in the league, could become more vulnerable.
"Being a running back, you're going to get beat up as the year goes on. That's why it's nice to have a couple backs who can stay in the flow of the game if you need a break here or there," McCoy said.
Last week against New Orleans, Hillman had seven of Denver's 20 carries in the first half and another seven in the second half. His season-high 31-yard gain in the third quarter essentially summed up all his potential and his downside in one play. He found a big hole in the left side of the Saints defense and was accelerating in the open field, but a New Orleans defender was able to punch the ball out because Hillman was holding it a bit loosely.
The fumble went out of bounds -- no damage done -- and the Broncos scored a touchdown on the drive. Hillman learned his lesson; he's been learning a lot from his teammates, including Manning.
"You've got to have accountability when you play with him," Hillman said. "You've got to know what you did wrong and you've got to actually be on your 'A' game at all times. He kind of helps you out but most of the time it's on you. So, you have to grow up a lot faster than if I was with somebody else."
Says receiver Brandon Stokley, who has played five of his 15 NFL seasons alongside Manning: "You can imagine a 20-year-old trying to come into this type of situation. I think he's done a great job and I think he'll continually improve and get better just as the game kind of slows down for him. I couldn't imagine being that age and doing what he's doing right now."
Hillman said all the time he's spending with the veterans does, indeed, make him better. He also knows there's not much time for learning curves when he's playing with 30-something veterans in search of Super Bowl rings.
"They expect me to come here like I'm 25 and a vet," Hillman said.
Notes: QB Peyton Manning earned AFC Offensive Player of the Month honors, the fifth time he's received the award. Only Patriots QB Tom Brady has more, with six. Manning completed 77 of 104 passes for 951 yards with nine touchdowns with one interception in three games in October. ... The Broncos are 1-11 in their last 12 games in which they've traveled two or more time zones to the east (11 in the Eastern time zone, one in London). For the second straight season, coach John Fox is bringing the team east two days before the game to try to get acclimated to the time change. "I love it. Wish I could do it every week. Home games, as well," said Broncos CB Champ Bailey. ... Fox said doctors have regulated CB Tracy Porter's medicine to control seizures and he was cleared for full practice Thursday. Porter hasn't played since Nov. 7.