Mason is questionable to return to Thursday's game against the Seahawks due to a shoulder injury, Tom Pelissero of NFL Network reports.

EDGE Analysis

Mason walked off the field with trainers after a 14-yard run midway through the second quarter. The severity of the issue isn't clear, but Isaac Guerendo will take over as the 49ers' lead back while Mason is sidelined. After being evaluated in the locker room, Mason was spotted on the sideline with his helmet, per Nick Wagoner of ESPN.com.

Mason rushed 14 times for 89 yards and caught his lone target of nine yards while coughing up a fumble in Sunday's 24-23 loss to Arizona.

EDGE Analysis

Mason lost a fumble on his final touch in the fourth quarter of Sunday's narrow loss. The rare folly cost San Francisco dearly in the defeat, but it was also the third-year back's first lost fumble of his career. Mason still produced well on a per-touch basis and remains the unquestioned starter until Christian McCaffrey (calf/Achilles) returns from injury. A road tilt against the Seahawks on Thursday Night Football is on tap for Mason and the 49ers in Week 6.

Mason rattled off 24 carries for 123 yards and a touchdown while adding 37 receiving yards on two receptions (three targets) in Sunday's 30-13 win over New England.

EDGE Analysis

Mason continued to dominated the backfield touches in San Francisco sans starter Christian McCaffrey (calf/Achilles). The only other active running back to receive a carry in Sunday's run-heavy gameplan was rookie Isaac Guerendo, who fumbled that carry away for the 49ers' lone turnover. Mason has provided 20+ carries, 100+ rushing yards with at least one touchdown in three of his four starts. The Georgia Tech product will make at least two more starts while CMC continues to recover on injured reserve, making Mason a top-tier play against the Cardinals next Sunday.

Mason rushed 19 times for 77 yards and caught both of his targets for 11 yards in Sunday's 27-24 loss to the Rams.

EDGE Analysis

Mason failed to extend his touchdown streak to three games in Sunday's loss, but the fill-in starter still managed to provide fantasy managers with solid production despite his team's loss. The 25-year-old has rushed for 324 yards and two touchdowns while filling in for Christian McCaffrey (calf/Achilles) through three games this season. Mason remains a strong fantasy play heading into Sunday's tilt against the Patriots.

Mason took 20 carries for 100 yards and a rushing touchdown while bringing in his lone target for four yards in Sunday's 23-17 loss to Minnesota.

EDGE Analysis

Mason followed up his impressive Week 1 fantasy performance (28/147/1) with another game of 100-plus rushing yards and his second touchdown of the season. Savvy fantasy managers who snagged Mason when starter Christian McCaffrey (calf/Achilles) and backup Elijah Mitchell (knee) were ruled out prior to last week's win over the Jets have been rewarded handsomely. What appeared to be a hot short-term add is beginning to look like an league-changing acquisition after the aforementioned CMC was placed on injured reserve prior to Sunday's defeat (Week 7 earliest potential return). Mitchell has been ruled out for the entire year, so Mason is set to occupy the lead role in Kyle Shanahan's vaunted zone-run offense for roughly the first half of the fantasy campaign. It would behoove GMs in all fantasy formats to make sure that the Georgia Tech product is not lingering on their league's waiver wire ahead of Sunday's tilt against the Rams.

Mason's teammate Christian McCaffrey was placed on IR on Saturday due to an Achilles/calf injury.

EDGE Analysis

With Elijah Mitchell out for the season, the backfield might now continue to pretty much belong to Mason -- who had a 28-147-1 line in Week 1 -- until at least Oct. 10, the first date that McCaffrey is now eligible to return. Mason is probably long gone in almost every league by now, but all managers should at least take a peek to see if he's somehow still hiding on a waiver wire, Those who drafted him in a deep reserve round or spent some modest FAAB money ahead on him of Week 1 are now looking at a potential GameStop type of ROI on a modest investment.

Mason is slated to serve as the 49ers' No. 1 running back Sunday at Minnesota and beyond with the news that Christian McCaffrey (calf/Achilles) is a candidate for injured reserve, Matt Barrows of The Athletic reports.

EDGE Analysis

Coach Kyle Shanahan relayed Friday that San Francisco is considering an IR stint for McCaffrey due to the Achilles tendinitis that is plaguing him at the moment. Shanahan also noted that Thursday's practice was the worst for McCaffrey so far in terms of pain, according to Nick Wagoner of ESPN.com. The 49ers have yet to make a decision on McCaffrey past this weekend, but Mason at the very least will start Sunday on the heels of 29 touches for 152 yards from scrimmage and one rushing TD in the Week 1 win against the Jets. Meanwhile, Deebo Samuel figures to be in the backfield mix as well after handling eight carries Monday night.

Mason carried the ball 28 times for 147 yards and a touchdown while catching one pass for five yards in Monday's 32-19 win over the Jets.

EDGE Analysis

Mason filled in for injured starter Christian McCaffrey (calf/Achilles) in Monday's season opener and took full advantage of the opportunity with a career night against a talented defensive unit. The Georgia Tech product couldn't replicate CMC's receiving production, but he averaged 5.3 yards per attempt as a rusher while finishing with the highest fantasy score for San Francisco in the team's first win of the regular season. McCaffrey's absence seems to be a precautionary move by the team, so Mason's big fantasy day may be short lived. It wouldn't hurt to make sure the power back is rostered ahead of this weekend's tilt against Minnesota.

Mason is slated to be the 49ers' starting running back Monday versus the Jets with Christian McCaffrey (calf/Achilles) inactive for the contest, Nick Wagoner of ESPN.com reports.

EDGE Analysis

Mason will step in for McCaffrey for at least one game due to the calf/Achilles injury that has plagued the latter since early August. In 33 regular-season games in his two-year career, Mason has averaged 5.6 YPC on 83 rushes, hauled in three of four targets for 31 yards and scored four rushing TDs. Elsewhere in the backfield, Isaac Guerendo and Patrick Taylor are the 49ers' other available options.

Mason's backfield mate Elijah Mitchell (undisclosed) was placed on season-ending injured reserve Tuesday, David Lombardi of The Athletic reports.

EDGE Analysis

Reports of Mason challenging Mitchell for the second spot on the depth chart actually predate Mitchell's injury troubles this summer, with the Niners apparently impressed by Mason's combination of size (5-foot-11, 223 pounds) and passing-down skills. He's no match for Mitchell in terms of speed, but that may not matter much for fantasy if Mason ever finds himself in the starting lineup under coach Kyle Shanahan. While Christian McCaffrey (calf) seems to be on track for Week 1 against the Jets, there's always considerable injury risk for a running back that piles up snaps and touches the way CMC does. While unlikely to have standalone value while McCaffrey is healthy, Mason is one of the more valuable backup RBs to stash on a fantasy bench -- and he should remain so unless rookie fourth-round pick Isaac Guerendo makes a push up the depth chart after missing most of the summer with a hamstring injury.