One reason, actually.
Daryl Richardson, the Rams' rookie seventh-round draft choice, has given the offense a jolt with his speed and breakaway ability. He has 53- and 44-yard runs this season. Those are two of the Rams' three longest rushes since the start of the 2010 season. Jackson's 47-yard scoring run in the 2011 opener was the other.
Richardson has 246 yards and a 5.2-yard average through six games. If we watched the Rams play without knowing anything about the legacy Jackson has built in St. Louis, would we conclude through performance alone that Jackson was the Rams' best option?
We might, but it wouldn't be automatic.
Both backs are going to play, but this dynamic is a new one for the Rams. The team has not had a viable alternative to Jackson since Marshall Faul played his final down in 2005, Jackson's second season. The No. 2 back in St. Louis hasn't commanded many carries before this season.
Cadillac Williams, Kenneth Darby, Antonio Pittman, Brian Leonard and Stephen Davis have finished second to Jackson in rushing yards for the Rams since Faulk retired. They had between 152 and 361 yards rushing in a given season. Richardson is on pace to surpass 361 yards in the next three games and possibly sooner if Week 6 was an indicator. Richardson had 11 carries for 76 yards against the Miami Dolphins last week.
In the past, Jackson knew he would get enough carries over the course of 16 games to get his 1,000 yards. He has rightfully taken pride in the streak. There could be enough production to go around for Jackson to keep alive the streak even with Richardson playing a significant role in the offense. Both players were productive as the Rams amassed 462 yards against the Dolphins.
Through six games, Jackson is on pace for 861 yards. Richardson is on pace for 656. Jackson was on a slower pace at this point last season, but he caught up with at least 128 yards in three consecutive games beginning in Week 8. No other Rams running back got more than three carries in any of those games.
The chart shows production by down for Richardson and Jackson. The final column shows percentage of rushes resulting in first downs. The percentage is much higher for Jackson on third down because he has five carries on third-and-1, plus two others with fewer than four yards needed for a first down. Richardson's third-down carries have come with 7, 12, 13, 17 and 24 yards needed for a first down, according to ESPN Stats & Information.
Note: Rams coach Jeff Fisher addressed the one-two combination in his conversation with reporters Thursday.
"It's been working and we'll continue it," Fisher said. "I'd still like to see 'Jack' get at least about two-thirds of the carries because he’s got the experience, and Jack is one of those that he almost needs to get rolling. He needs to get going, so we’ll continue to work with that, but we were pleased with the results last weekend."
Related: Rick Venturi's film review on the Rams' running backs at Miami begin at the five-minute mark of this clip.