Mason (hamstring) had two carries for six yards in Friday's preseason opener against the Raiders.

Mason only played one drive before giving way to Benny Cunningham, who will likely serve as the passing-down back to start the season. Todd Gurley (knee) is expected to miss the first few games of the regular season, but he'll eventually provide a major threat to Mason's workload.

Mason (hamstring) did not practice Saturday but did some light running on the sidelines, according to Joe Lyons of the St. Louis Post-Dispatch.

Mason pulled up with a hamstring issue on Thursday and it appears to still be bothering him. If he's running, however, the injury cannot be too serious and he shouldn't miss much preseason time. The Rams will likely be cautious with their starting running back, however.

Mason left practice early Thursday with tightness in his hamstring, Joe Lyons of the St. Louis Post-Dispatch reports.

Mason is in line for the majority of the Rams' carries right now, so him missing any time would hurt St. Louis. The injury didn't appear serious, but hamstring injuries have a way of persisting.

Though Todd Gurley -- the No. 10 overall pick in the 2015 draft -- will not begin training camp on the Rams' PUP list, the St. Louis Post-Dispatch suggests that Mason is still expected to "get the lion's share" of the team's carries once the regular season kicks off.

Given that Gurley suffered a torn ACL on Nov. 15, the report indicates that the Rams are not inclined to rush him back, and with that in mind we expect the rookie to be eased into the team's backfield mix out of the gate, thus creating an early-season window for Mason to maintain fantasy utility. Down the road, however, it's clear that Gurley is viewed as the team's running back of the future, meaning that Mason's role figures to evolve into that of a more of a backup/complementary one once Gurley is fully up to speed.

Mason will have some competition for the No. 1 running back spot next season with the drafting of Todd Gurley, the St. Louis Post-Dispatch reports.

Mason had an up-and-down 2014 season, with a couple standout games along with a few clunkers. That's to be expected from a rookie, but the Rams using a first-round pick on Gurley makes one wonder whether St. Louis thinks Mason is its long-term workhorse. Mason is likely to start the year as the starter with Gurley still recovering from injury, so he will have to make the most of those first few games.

Mason ran 11 times for 28 yards and caught 3-of-4 targets for 29 yards in Sunday's loss at Seattle.

Outside of a 13-yard run at one point, Mason had trouble finding lanes against a stout Seahawks' rush defense. He became the Rams' workhorse back in the second half of the season, finishing with 765 yards four touchdowns. While he doesn't possess true home-run speed, he shows a nice burst and runs with good power. Unless St. Louis selects another RB in next season's draft, we'd assume that Mason will be given an opportunity to start again in 2015.

Mason had 13 carries for 76 yards and a touchdown in Sunday's 37-27 loss to the Giants.

The Rams were not able to run the ball as frequently as they would have liked, but Mason ran very with with his limited opportunities, averaging 5.8 yards per carry. He'll face a much tougher test in the Rams' Week 17 finale against Seattle.

Mason lost a fumble and gained just 33 yards on 13 carries in Thursday's 12-6 loss to the Cardinals.

Mason didn't find much room to run against a stout front seven, and the Rams mostly leaned on their passing game while trying to erase a deficit in the second half. The good news for owners is that Mason still dominated the carries, with Benny Cunningham getting just two for four yards. Of course, Cunningham also caught 3-of-4 targets for 23 yards, while Mason's lone target fell incomplete. Mason has just 12 catches through 10 games, with none in his last two contest. Don't expect much in the way of receptions, but the rookie should find bigger holes to run through in Week 16 against the Giants.

Mason had 20 carries for 66 yards in Sunday's 24-0 win over Washington.

A bit of a letdown performance for Mason after he accumulated 164 yards and two touchdowns in Week 13 against the Raiders, but Mason remains the clear top running back in St. Louis, as backup Benny Cunningham had just three carries and Zac Stacy had none. A breakout in Week 15 seems a bit unlikely, as the Rams will face off against a Cardinals defense allowing the sixth-fewest rushing yards per game this season.

Mason had 14 carries for 117 rushing yards and two touchdowns, as well as three catches on four targets for 47 receiving yards and another score during Sunday's 52-0 win over the Raiders.

Mason was absolutely unstoppable Sunday, scoring on a 35-yard pass play in the first quarter, then adding an 89-yard rushing touchdown in the second quarter before capping off his day with an eight-yard touchdown in the fourth to make it 45-0. While Zac Stacy has technically been listed as the top running back in St. Louis, the job is clearly Mason's and the offense is now starting to revolve around him. He's rushed for at least 110 yards in two of the last three games, though he could have a tougher go of it in Week 13 against the Redskins, who are allowing the ninth-fewest rushing yards per game this season.

Mason had 16 carries for 62 yards and caught 1-of-2 targets for 26 yards in Sunday's 27-24 loss at San Diego.

Other than a 21-yard rush, Mason was held in check against a swarming Chargers' defense. While it was a quiet game from a statistical standpoint, Mason continues to dominate the action in the Rams' backfield, as Benny Cunninham was the only other RB to carry the ball, rushing for 18 yards on four totes. Mason has an opportunity to rebound next week, facing a porous Raiders' rush defense.

Mason had 29 carries for a career-high 113 rushing yards and one catch on two targets for one receiving yard Sunday against the Broncos.

Facing off against a Broncos defense that came into the game allowing the fewest rushing yards per game this season, Mason took full advantage of his increase in carries, as the Rams did all they could to milk the clock on offense to keep the ball out of Peyton Manning's hands. Mason's 29 carries were 10 more than his previous season-high, and he ceded only two carries to backup Benny Cunningham and two to wideout Tavon Austin. It's clear that the Rams' backfield belongs to Mason and he'll look to keep his solid play going in Week 12 against a Chargers defense ranked 17th against the run this season.

Mason had 14 carries for 48 yards in Sunday's 31-4 loss at Arizona.

Mason got banged up with an unknown injury in the fourth quarter, although he was able to return to the game, running a number of pass patterns, while St. Louis was in comeback mode. While he still hasn't been named the Rams' starter, he's seeing most of the work in their backfield, with at least 14 carries in three of the last four games. The rookie RB is not regarded as a great pass catcher, but he showed decent receiving skills Sunday, posting career highs in receptions, targets and yardage, with four, six and 33, respectively. If the Rams plan on using him a little more as a receiver, his value would obviously increase. Meanwhile, Benny Cunningham had four carries for 12 yards and a touchdown and caught 2-of-4 targets for 16 yards. Based on recent usage patterns, it appears as though Mason will get most of the work in Week 11, facing a solid Broncos' rush defense.

Although Mason received the bulk of the carries last Sunday, he has not been named the full-time starter, the St. Louis Post-Dispatch reports.

Mason had 19 carries for 65 yards against a tough 49ers defense on Sunday, and saw nearly 70 percent of the snaps. He will likely see the bulk of the snaps going forward no matter who the official starter is, but he next goes against a Cardinals team which was the first to keep DeMarco Murray to less than 100 yards all season.

Mason had 19 carries for 65 yards and lost eight yards on his only reception in Sunday's 13-10 win at San Francisco.

Mason ripped off a 21-yard run at one point, but was otherwise held in check. On a positive note, Mason was the primary ball carrier Sunday, as Benny Cunningham had just four carries for 10 yards, while Zac Stacy did not touch the ball a single time. The rookie runner has a tough matchup next week at Arizona, which has been incredibly stingy against the rush this season.

Mason had seven carries for a team-high 32 rushing yards, as well as one catch on one target for one receiving yard Sunday against the Chiefs.

While Mason led the team in carries and rushing yards, his eight total touches were matched by Zac Stacy (five carries for 17 rushing yards and three catches on four targets for 20 receiving yards) and were only three more than Benny Cunningham (four carries for 27 yards and one catch on one target for eight receiving yards). Making the running game situation even cloudier, the Rams lost center Scott Wells to an elbow injury, tackle Jake long to a knee injury and guard Rodger Saffold to a shoulder injury. And last but not least, the Rams will face off against a 49ers defense in Week 9 that is ranked fifth in rushing-yards allowed per game this season, making Stacy a tough fantasy start next Sunday.

Mason had 18 carries for 85 yards and a touchdown Sunday against the Seahawks.

Offensive coordinator Brian Schottenheimer said earlier this week that he was going to split the backfield touches between Mason, Benny Cunningham and Zac Stacy until he found a hot hand, but he fully went with Mason on Sunday, as Cunningham finished with two carries for three yards and Stacy didn't get a single touch. Cunningham did contribute in the passing game, catching five passes for 46 yards and a touchdown, but it looks like Mason has taken over the carries out of the backfield. Up next is a Week 8 matchup against a Chiefs defense that is allowing 127.4 rushing yards per game this season, the 10th-highest average in the NFL.

Mason gained 40 yards on five carries and 12 yards on one reception in Monday's 31-17 loss to the 49ers.

Active for the first time in his career, Mason caught a pass on the game's first drive, then later in the quarter ripped off consecutive carries of 24, three and six yards to set up a touchdown pass to TE Lance Kendricks. Mason didn't get another touch until the third quarter, and while he split the carries with Zac Stacy and Benny Cunningham, it was the rookie that easily led the team in rushing. Mason at least did enough to hold a small role in the offense, and the 1-4 Rams might consider using more of the third-round rookie next week against Seattle. Fellow St. Louis running backs Zac Stacy and Benny Cunningham have been solid but unspectacular this season.

Mason is active for the first time this season Monday against the 49ers, the St. Louis Post-Dispatch reports.

With fellow running back Chase Reynolds inactive, Mason will be in uniform for the Rams, but a wait-and-see approach is in order with the third-rounder.

Mason is inactive for Sunday's game against the Vikings, Jim Thomas of the St. Louis Post-Dispatch reports.

Mason could factor in down the road, but at this it looks like he's an injury away from fantasy relevance.