The San Francisco 49ers and Arizona Cardinals will kick off their Week 4 contest on Sunday at 1:05 p.m. PT from University of Phoenix Stadium. While the Niner Faithful will be keeping an eye on key 49ers players like Brian Hoyer, Pierre Garçon, DeForest Buckner, and Carlos Hyde – assuming he plays – there are a number of Cardinals players who could be factors in the matchup.

We reached out to our friends over at Cards Wire and spoke with site editor Jess Root (@senorjessroot), who was kind enough to share his three key Cardinals players to keep an eye on during Sunday's game. Below are those three players.

Of course, you can read all of Root's coverage of the Cardinals at Cards Wire.

Andre Ellington

Running back Andre Ellington looks to carry the load for the Cardinals in the absence of David Johnson. Arizona head coach Bruce Arians has shown a willingness to use multiple running backs in his absence, with Chris Johnson getting the bulk of the touches on Monday against the Dallas Cowboys, but Root believes Ellington could be a key player on Sunday against the 49ers. While Johnson had more carries on Monday, Ellington was actually in the game for more plays.

"With the running game in bad shape because of the loss of David Johnson, Ellington has the potential to do what he did his rookie season," Root told 49ers Webzone. "He had a solid game in Week 3. His ability to make plays in the passing game and the return of aggressive running make him a player to watch."

Ellington has just one career game rushing for over 100 yards. That game took place during his rookie season in 2013 and saw him carry the football 15 times for 154 yards and a touchdown in a Week 8 performance against the Atlanta Falcons.

Against Dallas, Ellington had five carries for 22 yards but also contributed five catches for 59 yards. However, he is still seeking his first touchdown since 2015. As Root noted, Ellington's role in the passing game may be key for the Cardinals. Of the 10 catchable passes thrown Ellington's way this season, he has caught all of them, according to Pro Football Focus. His yards per route run rank 11th among running backs this season.

Larry Fitzgerald

On Monday, wide receiver Larry Fitzgerald had his best statistical performance since a Week 10 contest last season against the 49ers. That 2016 matchup saw him haul in 12 catches for 132 yards. Against Dallas, Fitzgerald caught 13 passes for 149 yards.

"He is coming off his best game in years and he has incredible numbers in his career against the 49ers," said Root.

The 49ers have faced the 14-year veteran 26 times throughout his career. Not only has Fitzgerald had good numbers against the 49ers in recent seasons, but his past two performances at home against San Francisco have seen him post 21 catches for 266 yards and two touchdowns.

Fitzgerald has a very favorable matchup against the 49ers and will likely line up across from cornerback K'Waun Williams, who was given a three-year contract extension this week, in the slot. The matchup is among the best for a wide receiver, according to Pro Football Focus, with Rashard Robinson projected to match up against John Brown.

Fitzgerald is the league's fourth-best graded receiver catching the football deep, again, according to Pro Football Focus. The 49ers defense allowed two 100-plus-yard receivers against the Los Angeles Rams and gave up six catches for 20-or-more yards in the game.

"He's been great his whole career," 49ers head coach Kyle Shanahan said on Wednesday when asked about Fitzgerald. "He was great in college and he's still great. Larry is, people talk about him losing speed and stuff, whether he has or hasn't it doesn't matter. When you can make cuts like he can, when you can play as violent as he can, when you have the hands that he does, everyone sees what he does for them in the pass game because you get the numbers and everything, but he doesn't take a down off in this league.

"And to play that long that way where you'll throw your body around as a blocker, you fight for yards after the catch when the ball is in your hand, he's a fearless competitor. There's no doubt he's talented, but the competitor in him is what separates him from the rest."

Deone Bucannon

"He's back!" Cardinals cornerback Patrick Peterson shouted in the team locker room this week. "The original money 'backer is back!"

Peterson was referring to Cardinals linebacker Deone Bucannon, who finished his first full week of practice since suffering severe ligament damage in his ankle during a late-2016 game against the Miami Dolphins.

"He will make his season debut, finally returning from ankle surgery," said Root. "Haason Reddick has played well mostly in his place, but Bucannon will bring speed and hitting."

Arians agreed with that assessment, saying that Bucannon brings "a lot more speed and a lot more toughness" to the Cardinals defense. Prior to this week, he hasn't really experienced any real hitting since his injury. Sunday's game will be his first big test.

"I pride myself on just leaving it all out there for my teammates," said Bucannon this week. "I'm not going to back down from any challenge. My teammates know that. I'm a physical guy and I like being in the mix. I've always been a competitor."

Bucannon may not see the majority of playing time against the 49ers on Sunday, but he will be involved, according to Arians. He had an opportunity to return as early as the Cardinals' season opener, but he rolled his ankle on his first day off of the physically-unable-to-perform list during training camp.

A big thank you to Jess Root for talking to us about the Cardinals' key players for Sunday. Be sure to give our friends over at Cards Wire a visit for more information on the 49ers' next opponent.