Who Should I Start? Alexander Mattison or Corey Kiner

Tuesday, August 12, 9:32 AM

Miami Dolphins running back Alexander Mattison (neck) was officially placed on injured reserve on Monday. Mattison injured his neck during a preseason game against the Chicago Bears on Sunday and later went for surgery. It was announced on Monday that he would miss the remainder of the year, with the team placing him on IR just as a procedural move to clear roster space. Mattison's absence will open up reps for second-year running back Jaylen Wright and rookie Ollie Gordon II behind starter De'Von Achane.

Sunday, August 10, 5:46 AM

Rookie Corey Kiner had a solid day in his professional debut. In the 49ers' preseason opener against the Denver Broncos, Kiner led San Francisco's backfield in touches and yards, taking 10 carries for 45 yards and catching one pass for a two-yard gain. He also served as a kick returner, bringing one back for 17 yards. Kiner, an undrafted free agent, comes to the 49ers after back-to-back 1,000-yard seasons as a Cincinnati Bearcat and figures to see a lot of work in the preseason. San Francisco is unlikely to put Christian McCaffrey's health on the line so early, and Isaac Guerendo (shoulder) and fellow rookie Jordan James (finger) are set to miss multiple weeks while nursing injuries. Kiner will have his next chance to impress next week against the Las Vegas Raiders.