49ers' Isaac Guerendo: Lead role awaits

Guerendo is expected to take over as the 49ers' lead back for the remainder of the regular season after head coach Kyle Shanahan said Monday that both Christian McCaffrey (knee) and Jordan Mason (ankle) are on track to be placed on injured reserve this week, Nick Wagoner of ESPN.com reports.

Shanahan noted that McCaffrey is facing a six-week recovery for the PCL sprain he sustained in Sunday's loss to the Bills, while Mason is dealing with a high-ankle sprain that will keep him out through Week 17, and quite likely, the Jan. 5 regular-season finale in Arizona. The injuries vault Guerendo to the top of the depth chart as the lone healthy back on the 53-man roster, though the 49ers are expected to elevate Patrick Taylor from their practice squad and add another running back to provide further depth ahead of this Sunday's game against the Bears. A rookie fourth-round pick out of Louisville, Guerero has seen limited action this season but has averaged a strong 5.9 yards per carry while scoring two touchdowns on his 42 totes and adding five catches for 19 yards on six targets. Guerendo is a size/speed specimen at six-foot and 221 pounds who recorded a 4.33-second 40-yard dash time at the NFL Scouting Combine. With a three-down role likely in the offing for the final five weeks of the season, Guerendo will be the top waiver-wire priority in fantasy leagues where he's available.