Running back David Johnson surges in for a one-yard touchdown run during the Cardinals' win against the 49ers last weekend.

Starting running backs will always be glorified in the NFL.

They are regulars in the end zone, touch the ball more than anyone but the quarterback, and with the ever-increasing popularity of fantasy football, get analyzed breathlessly each week.

So it wasn't a surprise to see a great deal of consternation after the Cardinals placed Chris Johnson – the NFL's fourth-leading rusher – on injured reserve/designated to return with a tibial plateau fracture on Tuesday. The only way he plays again this season is if the team makes the Super Bowl.

"He was convinced it was a bruise, and it was going to be one week because he's tough," coach Bruce Arians said. "Then we got the MRI and it was a crack in it. He's pissed. I'm pissed. But that's football. We have to move on."

While there's no denying a move from Chris Johnson to rookie David Johnson for this week's game against the Rams will change the offensive attack, the potential repercussions may be overstated.

High-profile running backs Marshawn Lynch, Matt Forte, Le'Veon Bell, Arian Foster and Jamaal Charles have all missed at least three games this season, with the latter trio done for the year. In the 30 games those five running backs have played, their teams have gone a combined 11-19. Without them, their teams are 18-7.

Outcomes hinge on much more than just one player, of course, and every offense would jump at the chance to have those guys in the backfield. However, the presence of a high-profile tailback is clearly not a prerequisite to winning.

Undrafted rookie free agent Thomas Rawls has stepped in seamlessly for Lynch in Seattle, averaging a robust 5.6 yards per carry. Pittsburgh's DeAngelo Williams has an identical yards-per-carry average (4.9) as Bell did before he went down.

Little-known backs like Houston's Alfred Blue, Chicago's Jeremy Langford and Kansas City's Charcandrick West and Spencer Ware have filled in capably enough.

"I think running back is one of the easier ones (to replace)," Arians said. "Now it's different to replace Adrian Peterson, or a couple of guys like that. Chris was having a heck of a year, but David, given those same number of touches, I don't think would be far behind that."

While there is a ton of focus on running back production during the season, it may be more accurate to follow the money during free agency. Running backs don't get much coin, and the Cardinals' big move in March was to throw a five-year, $40 million deal at Pro Bowl guard Mike Iupati. A good offensive line can do wonders for whichever running back lines up behind them.

"You stick your blocks and you're able to create seams for whoever has the ball," left tackle Jared Veldheer said. "That's what we hang our hat on, the run game stuff."

The Cardinals were down their top two running backs – Ellington and Jonathan Dwyer – by this time last year.

Kerwynn Williams didn't miss a beat, as he was pulled up from the practice squad and ran 19 times for 100 yards in a win against the Chiefs on Dec. 7 and had 15 carries for 75 yards against the Rams four days later. He averaged 4.6 yards per carry in five games, 1.3 yards better than Ellington's average in 2014.

Williams has been on the practice squad for all but one game in 2015, and quarterback Carson Palmer said he was holding his breath in hopes another team didn't sign him to its active roster. Williams was promoted to the Cardinals' active roster in place of Johnson on Tuesday, and could see some carries with Ellington (turf toe) expected to sit.

"Hopefully I can live up to those high praises (from Palmer)," Williams said.

David Johnson leads the team with eight total touchdowns and is a threat both rushing the ball and catching it. He's averaged 4.0 yards per carry, not far off from Chris Johnson's 4.2, albeit in 161 fewer carries. He is expected to start on Sunday.

"It's not like I haven't been here throughout practice, in the game and preparing each week," he said. "It's nothing different. The only thing is that I'm playing a little bit more."

The Cardinals may take a dip in rushing production without Chris Johnson. It's also not out of the realm that a combination of Ellington, David Johnson and Williams matches or even surpasses the previous production.

It may not even matter if it's quibble over a handful of rushing yards. As long as the running game doesn't go completely belly up, the Cardinals are so talented in other areas they should remain among the NFL's best teams.

"Chris has been such a great running back for as long as I can remember, so we're definitely a different team, there's no doubt," Palmer said. "He was so great in pass protection. Obviously he had those plays where he bounced off guys and ripped off runs. He runs through arm tackles, he reads blocks really well – all those things he has, you don't replace.

"So definitely things are changing, but our goals are the same. We expect to win no matter who we play."