After tearing his ACL prior to the start of the 2018 season, the San Francisco 49ers had to wait a year to see their shiny new running back in action. Jerick McKinnon, formerly of the Minnesota Vikings, made his way off of injured reserve yesterday, but he may be back on it soon, according to Matt Barrows of The Athletic. The 49ers beat writer said, via Twitter,

One more 49er unlikely to play in the preseason: Jerick McKinnon. He experienced soreness after his first two practices and is being held back. He'll have a platelet-rich plasma injection to help speed up the healing process. Putting him on IR to start the season is an option.

As Barrows notes, McKinnon isn't yet back in full speed for the 49ers. The running back will have a platelet-rich plasma injection to attempt to cure the soreness. The procedure uses “injections of a concentration of a patient’s own platelets to accelerate the healing of injured tendons, ligaments, muscles and joints,” according to HCC.edu.

In the interim, Tevin Coleman and Matt Breida are the one-two running backs for San Francisco. Coleman, a pricey free agency addition, is nearing full-time starter status, while Breida, a contributor in 2018, is a scheme fit with experience with the team. Raheem Mostert stands as the third with McKinnon out.

The 49ers' depth at running back is amongst the best in the NFL. Though not boasting stars or superstars, each fits what head coach Kyle Shanahan demands, McKinnon included. Due to so, they can afford to play cautiously with McKinnon's injury.