Two games into the Kansas City Chiefs' 2014 season, Jamaal Charles and the running back unit were dealt an early blow.
With nine and a half minutes to go in the first quarter against the Denver Broncos in Week 2, quarterback Alex Smith handed the ball off to the two-time All-Pro running back.
After gaining just a yard, Charles was tackled to the ground and then limped off to the sideline. He had suffered an ankle injury that would keep him out of the rest of the game, and Knile Davis received the call as the next man up.
Now the primary running back, Davis carried the ball 22 times for a respectable 79 yards and two touchdowns the rest of the way in the Chiefs' 24-17 loss.
As Charles' injury would keep him out the next week against Miami, head coach Andy Reid was asked by reporters during the week whether or not he believed Davis was up for the challenge of starting.
"If it's work ethic that determines that and want to, I would tell you yes," Reid said. "Nobody has spent more time in the offseason than him working in the weight room, working on scheme and learning [than Davis]. He's a mature second-year player.
"I think everybody has confidence that he can step in and do a good job there."
Without its best player in Charles, the depth of the running back unit proved Reid right and was very good for the Chiefs early on in the season when they needed it.
Knile Davis ran the ball 54 times for 211 yards rushing and three touchdowns during the stretch Charles missed, and solely against Miami, Cyrus Gray and Joe McKnight had the best games of their respective seasons and possibly their careers.
McKnight, who entered the Miami game having never scored an offensive touchdown, caught six passes from Smith for 64 yards receiving and two of them. Gray, in the same situation as McKnight, also scored the first touchdown of his career while picking up 18 yards rushing in his four carries.
McKnight's season came to an end during the practice following Miami due to a ruptured Achilles tendon, and Gray, who wouldn't receive another carry all year upon Charles' return the following game, tore his ACL in Week 10 against Buffalo.
Charles returned in full health in Week 4 for the Chiefs' Monday Night Football matchup against the New England Patriots. In his first game back, he split carries with Davis, and the two combined for 199 yards on the ground.
Charles scored three total touchdowns in the 41-14 blowout win, and the game began a period of high efficiency for the seven-year veteran. He recorded at least 78 yards rushing seven times during the next eight games for an average of 5.24 yards per carry.
The biggest games of the year for Charles occurred in Week 6 and Week 10.
Needing exactly 16 yards to break the Chiefs' franchise record in career yards rushing, Charles got just that by running for a 16-yard touchdown in Week 6 against the Chargers.
Four games later in Week 10, he erupted for 159 yards on 20 carries and two touchdowns against the Seattle Seahawks, marking the only time he would exceed 100 yards rushing the entire season.
"I'm not saying there was any challenge there for him because he's Jamaal Charles," Reid said after the game. "He's a good football player and he keeps producing every week and he's done it for a number of years. He's a special player, very special player."
Charles' success rushing the ball in 2014 was once again due in part to fullback Anthony Sherman, who blocked for him and for the second year in a row, earned Pro Football Focus' highest overall fullback rating.
Against San Diego in Week 6, Sherman scored the second touchdown of his career off of a screen pass.
Sherman, only relying on plays from special teams, also tied for second in the league with four forced fumbles, an unheard of feat for a player who didn't play a defensive snap all season.
Rookie De'Anthony Thomas, who did most of his damage with pass receptions and punt returns, finished the year with 113 yards rushing on 14 attempts, primarily on end-arounds and jet sweeps.
Thomas' lone offensive touchdown came as a result of a short Smith lateral pass ruled a rush.
Throughout the season, the Chiefs' running back contingent demonstrated that it could absolutely be the team's most talented unit.
In a year that no Chiefs wide receiver recorded a touchdown receiving, the running backs had nine, and led by Charles' 1,033 yards on the ground, they averaged 119.9 per game as a team, a mark that placed them at 10th in the NFL.
Charles' 14 total touchdowns in 2014 ranked him third in the league, only behind Marshawn Lynch and Dez Bryant, and his 33 touchdowns over the past two years is the most in the NFL.
"He enjoys the game," Chiefs general manager John Dorsey said of Charles on breakup day. "He likes to come to work every day, and you can't have enough of those guys on your team."
As the Chiefs set their focus on 2015, Charles, who has not been afraid to mention the Hall of Fame in the past, will look to stay on pace for it as the young depth at the position continue to learn from one of the game's greatest of all time.
Highlights from the Kansas City Chiefs' running backs in 2014.