Grant Cohn: Grading 49ers roster — who are the top five players?

NFL coaching staffs grade their players weekly. Sometimes more frequently.

These grades have nothing to do with past accomplishments. They reflect the coaching staff's view of each player's current talent and potential. You can bet Chip Kelly's staff evaluated the 49ers' roster throughout the offseason, and you can bet those evaluations were completely different than the ones Jim Tomsula's staff made last season.

Player values change from staff to staff depending on the styles of play the coordinators like to coach. Example: Aaron Lynch. He fit former 49ers defensive coordinator Eric Mangini's defense, so Mangini liked him. Started him in 13 of the 14 games Lynch played last season.

The new defensive coordinator, Jim O'Neil, runs a completely different scheme. He likes using outside linebackers in man-to-man coverage deep down the field, something Mangini never did. If Mangini made an outside linebacker cover a receiver, Mangini would ask him to cover a small zone near the line of scrimmage.

Lynch could handle a small zone. He cannot cover man to man. Not a fluid athlete. Needs to face the action. Should not turn his back on the quarterback.

Which means Lynch doesn't fit O'Neil's defense. And that probably is why O'Neil seems to prefer Eli Harold, a second-year outside linebacker who started only one game and recorded zero sacks as a rookie last season. But he can cover. So he grades high and Lynch probably doesn't.

With that in mind, here are the five players in ascending order I think Kelly's staff grades the highest.

5. Jimmie Ward

Under Mangini and Vic Fangio, Ward was a part-time player. A nickel cornerback. When the other team used three receivers, Ward covered the guy in the slot. When the other team didn't use three receivers, Ward stood on the sideline.

Ward won't do much sideline standing next season. The new coaches have moved him to the outside so he can play every snap because they think he's one of the best players on the team.

Ward hasn't played outside corner since high school. But he is by far the most athletic player in the Niners secondary. He could start at any position – corner, strong safety, free safety. Wouldn't matter.

During OTAs and minicamp, Ward gave up only a few short catches. He looked like a natural, although he did get penalized once for holding and once for pass interference. He probably will stop grabbing receivers as he gets more comfortable playing his new position.

4. Arik Armstead

Last season, Armstead played mostly on third downs. Passing downs. Mangini didn't trust the rookie first-round pick to stop the run.

Mangini had his reasons. Armstead is a former basketball player who looked more like a basketball player than a football player last year. Had very little muscle definition for a defensive lineman. Opposing teams would have run right at him if he played on running downs. Armstead was effective only as a pass rusher.

He's a totally different athlete this year. All of a sudden he looks like the strongest player on the team. Looks like Goliath, but bigger.

Now, Armstead is the focal point of the defensive line. O'Neil loves him. In the 3-4 base defense, Armstead plays defensive end — Ray McDonald's old position. And in the nickel defense, Armstead moves all around. On first and second down he plays right outside linebacker — Aldon Smith's old position. On third down, sometimes he plays defensive tackle — Justin Smith's old position — and sometimes he plays defensive end.

O'Neil expresses his creativity through Armstead.

3. NaVorro Bowman

Bowman led the league in tackles last season and earned his fourth All-Pro selection. Hall-of-Fame credentials.

Bowman is great at stopping the run. He might be the best run-stopping inside linebacker in the NFL. But he struggles in coverage, has struggled ever since he mangled his knee in the 2014 NFC championship game.

Bowman no longer changes directions quickly. Can't cover running backs or tight ends anymore. He's a liability on passing downs unless he's blitzing. So he can't rank any higher than third on this list. The Niners' top two players excel on all downs.

2. Carlos Hyde

Hyde's first-two seasons in the league, he accomplished nothing. Rushed for only 803 yards and missed 11 games to injuries. A disappointment.

Forget all that. I get the feeling Kelly sees Hyde as the best running back he ever has coached. Hyde is big, powerful, violent, elusive, and he thrives when the quarterback is in the shotgun. He's perfect for Kelly's spread offense.

The past two seasons, the 49ers tried to make Hyde a conventional running back who lines up in I-formations when the quarterback is under center. Tried to make Hyde the next Frank Gore. Bad fit. Hyde failed.

This coaching staff will let Hyde be Hyde, let him take every carry from the shotgun where he has averaged 5.3 yards per carry in the NFL. If he stays healthy, he could rush for 1,500 yards, catch 50 passes for another 500 yards and make the Pro Bowl.

1. Joe Staley

Staley is good at everything. He's an outstanding run-blocker, powerful enough to play right tackle or even guard. And he has exceptionally quick feet to protect the quarterback's blind side, which is why he plays left tackle.

Most fans know Staley can play, but may not realize how great his is. Linemen tend to go overlooked. For years when the Niners had both Steve Young and Jerry Rice, the highest-graded player on the team was defensive tackle Bryant Young. Fans didn't see him as the team's best player, but the coaching staff did.

Staley is this team's Bryant Young.

Grant Cohn writes sports columns and the 'Inside the 49ers' blog for The Press Democrat's website. You can reach him at grantcohn@gmail.com.