But for one day at least -- even against Jacksonville's league-worst rush defense -- Stacy was the cure for what's ailed the Rams' running woes.
“I thought Zac did a great job today,” quarterback Sam Bradford said. “I think he showed everyone what he was about. He ran hard, he ran physical, he ran downhill. I don't think you could ask for much more from him today.”
After teasing some adjustments to the running game after a performance that yielded 18 yards on 19 carries against San Francisco, Rams coach Jeff Fisher followed through by taking the reins from Daryl Richardson and handing them to Stacy as the rookie from Vanderbilt made his first career start.
For most of last week, it was Stacy getting the bulk of the work with the first-team offense. Later in the week, the Rams informed him he'd be the starter. Undeterred by the moment, the workmanlike Stacy simply went about his business against the Jaguars.
Although his day ended a bit earlier than he would've liked after leaving with a late rib injury, Stacy finished with 78 yards on 14 carries. His longest gain was 12 yards, which means he was moving forward more often than not when he got his chances.
Unlike the other backs on the roster, Stacy brings a more powerful running style that had been missing in the first four weeks. The Rams were 30th in the league in yards after contact going into Sunday's game with an average of 1.15 yards after contact per rush.
Yes, the offense had struggled to run block entering the game but Richardson, Isaiah Pead and Benny Cunningham hadn't exactly been running through arm tackles or making defenders miss in the open field. Stacy didn't do much of the latter Sunday but he did plenty of the former.
“He was just running very physical,” receiver Austin Pettis said. “I think that was the biggest thing that we needed. We were kind of secondary running in the first couple games and it wasn't working out for us. Whether it was a 10-yard run or a 2-yard run, he was sticking his nose in there and making sure he was going to get some yards for us positively. I think that opened up so much for us offensively.”
Stacy's 78 yards were more than the Rams had posted in their Week 2 game against Atlanta, a 69-yard outing that was the team's best performance until Sunday. Acting as the jump-starter for the running game, Stacy keyed a rushing performance that yielded 143 yards on 36 carries. That average would've been even better were it not for some late Bradford kneel downs.
“It's definitely a confidence booster for the run game,” Stacy said. “Coach Fisher, he loves that physical type of runner and that's one thing that we all emphasize in the running back room. We want to bring that physicality out there on the field so it was pretty much what we emphasized all week.”
To be sure, one solid performance against the league's worst rushing defense doesn't mean the Rams have found the magic potion to suddenly be the power running team they once were with Steven Jackson at running back.
There's little doubt that Stacy brings more of that physical presence than any of his fellow backs and has at least earned another start next week in a game that should be right up his alley against Houston.
“It's one game but that's pretty much the mentality I have week in, week out, being productive, being consistent,” Stacy said.
So long as Stacy continues to do what he did Sunday, he'll be doing something else consistently: starting.