Rams running back Benny Cunningham seemed like a threat to Zac Stacy's playing time in the offseason, but was largely a nonfactor through three games. However, a calf injury to Stacy Sunday could put Cunningham in line to start moving forward.
Cunningham was effective in Stacy's stead in Week 5, racking up 72 all-purpose yards on just 10 touches. He found the end zone on a 14-yard run in the third quarter, and showed he can fill in capably, if needed. However, the Rams have an extra day to prepare for Week 6 against the 49ers, with that game coming on Monday night, so Stacy may be able to get healthy.
Even if Stacy's injury proves serious, you might not want to write Cunningham into your starting lineup after picking him up on waivers. The 49ers are likely to provide an unkind welcome to Cunningham, as they have not allowed a running back to reach double figures in Fantasy scoring since Week 1.
Whether Stacy or Cunningham gets the start in Week 6, you might not find a starting Fantasy running back in St. Louis.