Over the final five weeks of the 2009 regular season, the home-stretch period after Nov. 30, there were 40 individual 100-yard rushing performances in the NFL, and nearly half of them were turned in by running backs who began the year as backups.
That percentage (19 of the 40 games) is a bit high, but not especially unusual. Late in any season, when injuries pile up and dictate that backups move into starting roles, or those franchises eliminated from playoff contention audition more young players with an eye toward the future, lesser-known running backs often distinguish themselves.
But perhaps not to the extent that backup running backs did this season.
A prominent player agent recently noted that, "A lot of times, December is for winning jobs the following season, or for getting yourself better established in the eyes of a team's coaching staff."
That has particularly been the case this season for one-time No. 2 tailbacks such as Jerome Harrison of Cleveland, Jamaal Charles of Kansas City, Jason Snelling of Atlanta and a few other young runners.
"Sometimes you have the talent, but you've got to get the [playing time] to really show people just what you can do," said Harrison, who started one game from 2006-08, but who moved into the starting lineup this season when 10-year veteran Jamal Lewis was sidelined by post-concussion effects. "It's really about making the most of your opportunities."
Harrison -- a fifth-round pick in 2006 who at 5-foot-9 and 205 pounds was considered by many to be too small to be an every-down back -- has certainly taken advantage of this chance. He started all five games in December, and after rushing for only 44 yards and averaging 2.6 yards a carry in the first two outings became a Lewis-type workhorse in the final three. In those games, Harrison averaged 35.3 attempts and 187 yards and scored five touchdowns. The burst of production included a game of 286 yards, the third-best in NFL history, at Kansas City on Dec. 20.
Unless Lewis reverses his decision to retire, Harrison, 26, will almost certainly go to the Browns' training camp in the summer as the starter.
But Harrison isn't the only back who, in the final stretch of the season, played himself into what figures to be a prominent role in 2010.
Charles moved to the top of the depth chart in Kansas City when the Chiefs released Larry Johnson, and started 10 games, including the final nine. He was particularly effective over the final four games, rushing 94 times for 658 yards (a 7.0-yard average) and scoring four times. In the season finale, Charles ran for 259 yards.
Carolina's Jonathan Stewart filled in for the injured DeAngelo Williams late in the season and registered a 206-yard game. While Williams probably will remain the starter for 2010, Stewart's performance further cemented the Panthers' 1-2 punch, and demonstrated to the Carolina staff he can take on an expanded workload. In Atlanta, former seventh-round choice Snelling started at both fullback and tailback, and posted 147 yards in the season finale. If he is healthy, Michael Turner remains the Falcons' No.1 tailback, but Snelling could push the often-injured Jerious Norwood for the main backup job in 2010. Houston rookie Arian Foster appeared in only six games. starting one, but could challenge for the No. 1 job with the Texans in 2010 after rushing for 216 yards in the final two weeks.
Seven of the 15 players who rushed for 1,000 or more yards this season, and a dozen of the league's top 30 rushers for 2009, began either this year or last year as backups. Eight of the top 10 rushing games for December, including the top four (all of them 200-yard performances), were authored by backups.
Said second-year Steelers tailback Rashard Mendenhall, who rushed for 1,108 yards this season in supplanting Willie Parker as the starter, after carrying only 19 times in an injury-shortened rookie campaign: "It's a high-[attrition] position, one where you can step in and make an almost immediate impact."
That was certainly the case in the final month of this season.
Len Pasquarelli is a senior writer for ESPN.com.