JaMycal Hasty is Mini-Marshawn Lynch

Raheem Mostert will be out at least the next three weeks with a high-ankle sprain. The 49ers will be in big trouble unless one of their backup running backs steps up in a major way.

Raheem Mostert will be out at least the next three weeks with a high-ankle sprain. The 49ers will be in big trouble unless one of their backup running backs steps up in a major way.

Fortunately for them, it looks like undrafted rookie running back JaMycal Hasty is a stepper-upper. In fact, he looks like a mini-Marshawn Lynch with his combination of quickness, explosion and violence.

Here's the evidence:

Exhibit A: 13:22 Fourth Quarter. First and 10 at SF 29.

This is Hasty's first carry of the game, and he gains nine yards. He runs off tackle and huge hole opens up because Rams defensive tackle Aaron Donald immediately jumps out of his gap -- he's a freelancer. So he creates the yards more than Hasty does, But Hasty explodes through the hole in a way only Mostert can. Jerick McKinnon doesn't have the burst McKinnon shows on this carry. And at the end of the run, Hasty lowers his helmet and bursts with rage in to a defender. You'd think Hasty is 220 pounds, but he's only 205. Mini-Marshawn indeed.

Exhibit B: 12:34 Fourth Quarter. Second and 1 at SF 37.

This is Hasty's second carry of the game, and this is a four-yard gain. But Hasty creates these yards on his own. Both guards give up penetration before Hasty receives the handoff. But Hasty makes two defenders miss with two quick jump cuts -- one off his right foot, and the next off his left. Each time, Hasty gets extremely low to the ground and explodes off one foot.

Exhibit C: 10:21 Fourth Quarter. First and 10 at SF 48.

Now we're at Hasty's fourth carry of the game. This is an outside zone run to the left, and the blocking falls apart right away -- Trent Williams and George Kittle both fall down while blocking. Three defenders converge on Hasty at once. But he makes a surprisingly quick cut through two of them, spins off one tackle and almost gets away but a third defender's helmet clips Hasty's ankle. Gain of four. Easily could have been a loss of two.

Exhibit D: 3:24 Fourth Quarter. First and 10 at SF 25.

This is Hasty's best run of the game, it's his seventh carry and it's a 10-yard gain up the middle. It starts out as a toss to the outside, but the Rams set the edge by pushing Kittle into the backfield and force Hasty to cut back. Fine by Hasty. He instantly spots the cutback lane, make two jump cuts back to back off his right foot, jukes safety Taylor Rapp and finishes the run with violence. Hasty always finishes his runs with violence. He's a surprisingly-hard-running scat back who has more juice than any other running back on the 49ers other than Mostert. The 49ers need to give Hasty at least 12 carries per game until Mostert comes back.

Watch the full film breakdown below: