How the Alfred Morris signing shakes up the 49ers’ running back depth chart

The San Francisco 49ers are bringing in veteran Alfred Morris to help a depleted running back crop this preseason, although it’s possible Morris pushes some talent off the 53-man roster when Week 1 arrives.

Injuries have bit the San Francisco 49ers hard this preseason, and running back has been one of the areas hit the hardest.

The Niners lost second-year tailback Matt Breida to a shoulder injury during their exhibition opener versus the Dallas Cowboys last Thursday. On Sunday, projected starting running back Jerick McKinnon suffered an apparent knee injury — later, an MRI revealed it was a calf strain.

With two of his top tailbacks sidelined for the foreseeable future, head coach Kyle Shanahan told reporters Monday the team’s intention for bringing aboard veteran running back Alfred Morris, pending a physical.

“Alf did a great job for us for the two years I was with him,” Shanahan said. “It’s not flashy but he runs extremely hard. He’s very reliable. He’s always been able to – you block it for zero, (he) usually can get at least one. He’s a hard-nose runner, you can keep handing the ball off to who’s very reliable.”

Morris, 29 years old, spent time working under Shanahan when both were with the Washington Redskins back in 2012 and 2013. In 2012, Morris racked up an impressive 1,613 rush yards with 13 touchdowns on the ground.

He followed with two more Pro Bowl campaigns in 2013 and 2014, respectively, and had over 1,000 rush yards those two years.

After spending the last two years backing up Dallas Cowboys running back Ezekiel Elliott, Morris could push some of the Niners’ own depth tailbacks for a roster spot this season. Shanahan indicated such during Monday’s presser.

McKinnon is safe, barring further injury complications. Breida likely is too. After that, though, things get interesting. Second-year tailback Joe Williams is vying for a roster spot after being redshirted with an ankle injury his rookie season. Williams has been impressive throughout training camp so far, but Morris might change the number of reps Williams sees between now and roster cuts in September.

Another runner affected is Raheem Mostert, who led all ball carriers with 57 rush yards during San Francisco’s 24-21 win over Dallas last week, but figures to be more of a special teams contributor if he makes the 49ers’ regular-season roster.

That “if” looms a bit larger for Mostert now.

Morris’ presence puts a bit more pressure on runners like Williams and Mostert. But it’s going to take a massive effort from the veteran to push out either guy off the roster this season. Both Williams and Mostert were on the roster bubble entering training camp already, so that doesn’t change. And the Niners needed some extra help and another camp body, given the injuries to both McKinnon and Breida.

What likely happens is Morris sees a number of practice reps over the remainder of training camp, probably getting some work in with the second- and third-string units during San Francisco’s remaining preseason bouts. After that, it wouldn’t be surprising if Morris is cut.

Unless he makes it impossible for Shanahan to take that course of action.