Our "Four Downs" training camp preview concludes with a look at which players will have the greatest impact on the San Francisco 49ers success or failure in 2018. Check here for last week's edition that covered reasonable expectations for Jimmy Garoppolo.

First Down: What is the most anticipated position battle?

Joe Fann: Jimmie Ward vs. 49ers Defensive Backs

The 49ers clearly like Ward a lot. They wouldn't be making him the highest-paid player on defense if that wasn't the case. But it remains to be seen how they're going to get Ward on the field in 2018. The coaching staff has been steadfast in Ward's move from safety to cornerback. There also hasn't been any indication that Ward is going to get reps at nickel corner. That means the team's 2014 first-round pick could open the year as added depth at cornerback behind starters Ahkello Witherspoon and Richard Sherman. He'd be the primary insurance policy on Sherman as well. However, maybe Ward will play so well during camp/the preseason that he forces his way onto the field in Week 1.

Keiana Martin: Right Guard

Unlike years prior, there is only one starting spot that is truly up for grabs and that's at right guard. The 49ers offered Laken Tomlinson a three-year extension this offseason and he appears to be a lock at left guard. That leaves former 49ers first-rounder Joshua Garnett, who missed the entire 2017 season with a knee injury, to compete with Erik Magnuson, Jonathan Cooper and Mike Person. Cooper, a former first-round pick, started 13 games with the Dallas Cowboys last season and enters camp coming off of a knee injury. Person makes his second stint with San Francisco and split first-team reps during OTAs with Garnett. With all healthy and slated to return for camp, the battle at guard is one to keep your eye on over the next few weeks.

Second Down: Who is the player with the most to prove?

Joe Fann: Richard Sherman

I don't think anyone is totally sure of what the 49ers have in Sherman coming off of his Achilles tear. He'll be an invaluable asset as a leader, sure, but will he be able to get back to being vintage Richard Sherman as a player? There's no overstating what that would mean for the 49ers as a whole. I believe there's a decent amount of pressure on Sherman as he bet on himself in contract negotiations. He seems certain that he can return to form. Everyone else will be eager to wait and see if that's indeed the case.

Keiana Martin: Jerick McKinnon

San Francisco has high expectations for the former Minnesota Vikings ball carrier. McKinnon put up a modest 570 rushing yards and three touchdowns as a third-down back in 2017. Kyle Shanahan believed in him enough to offer the free agent the fourth-largest contract for an NFL running back. McKinnon will take on a much larger role in San Francisco with the expectation of living up to his hefty contract.

Third Down: What is the most improved position group?

Joe Fann: Inside Linebacker

I think the additions of Fred Warner and, for all intents and purposes, Malcolm Smith make the 49ers linebackers a vastly improved group. The extra depth will help San Francisco weather the storm while Reuben Foster serves his two-game suspension. Between Foster, Warner, Smith and Brock Coyle, I believe the 49ers have four dependable options at inside linebacker. Other position groups I believe are better off in 2018 are offensive line and defensive back.

Keiana Martin: Offensive Line

When the 49ers secured their franchise quarterback this offseason, their next order of business was to protect their investment. Last season, San Francisco tied for tenth-worst in the league with 43 sacks allowed. San Francisco first set out to upgrade the interior o-line by signing center Weston Richburg at the start of free agency. They also added Cooper and Person. The re-loading continued with Mike McGlinchey as the 49ers first-round pick in the draft. The 49ers anticipate this overhauled offensive line to be a strength in 2018.

Fourth Down: What is the deepest position group?

Joe Fann: Defensive Line

There's depth all over the roster, but no more so than on the d-line. You have the projected starters: DeForest Buckner, Solomon Thomas, Arik Armstead and Earl Mitchell. Then there are the backups (and starting edge rushers) who could/should play prominent roles as well: Cassius Marsh, Jeremiah Attaochu, D.J. Jones, Sheldon Day, Ronald Blair and Julian Taylor. It's a diverse group that provides a combination of run-stopping ability as well as the prowess to generate an effective pass rush. It's sure to be a constant rotation with Buckner and Thomas as the centerpieces.

Keiana Martin: Wide Receiver

There is both good and bad news when it comes to San Francisco's pass catchers. It's a pretty good problem to have when you host a surplus of talented wideouts on your roster. On the contrary, there are a limited number of roster spots up for grabs. There are currently 11 receivers on the 49ers roster heading into camp. Last season, San Francisco kept just six on the 53-man roster. Pierre Garçon, Marquise Goodwin, Trent Taylor and Dante Pettis appear to be locks. That leaves the remaining candidates, notably Kendrick Bourne, Aldrick Robinson, seventh-round pick Richie James and Aaron Burbridge to battle it out for the final two-to-three open spots.