Broncos running back Ronnie Hillman went above and beyond in his first game replacing the injured Montee Ball Week 6 at the Jets, not only rushing for 100 yards to give the Broncos their best individual rushing performance of the season but also doing it against what at the time a top-five run defense.
Unfortunately, he'll have to prove himself all over again against San Francisco in Week 7. The 49ers rank seventh against the run, allowing 79.8 yards per game, and have given up the fifth-fewest Fantasy points per game to running backs this season. They limited the Eagles' LeSean McCoy to 17 yards on 10 carries in Week 3 and the Bears' Matt Forte to 21 yards on 12 carries in Week 2.
Then again, the Chiefs' Jamaal Charles and the Cowboys' DeMarco Murray did fine against them, so it's not like Hillman is an automatic sit for this matchup (in case he didn't show you that last week). But he's risky. If you need him to be your second running back, no problem, but if you're considering him for your flex spot, you might want to go with a wide receiver instead.