Last season, Jimmie Ward was being touted by the San Francisco 49ers coaching staff as the team's top cornerback. He figures to be a big component of the 49ers' defensive plans this season as well.

Ward enters this offseason as the team's highest-graded defensive back, according to Pro Football Focus, and is working on transitioning back to the position he played in college – safety. He also finished the 2015 season as the 49ers' highest-graded defensive back.

The 49ers are transitioning to a single-high safety scheme and Ward is expected to fill that role. He is entering his fourth season with the 49ers and has accumulated 110 tackles, two sacks, 20 passes defended, and two interceptions over his three seasons. The new coaching staff was impressed enough with Ward that the team picked up his fifth-year option earlier this month. That will keep Ward under contract through the 2018 season.

Why is Ward such a key piece to the 49ers' plans? Matt Barrows of the Sacramento Bee joined KNBR on Thursday and explained.

"He had played nickel coverage in college and played free safety and played more along the line of scrimmage," Barrows said. "The 49ers used him as a nickel cornerback initially. Then, his second year, he was more of a backup safety and then last year, he was a cornerback. This year, he's going to be a free safety. An Earl Thomas type of free safety. That could end up being the perfect spot for him.

"He's obviously got good coverage skills. He's very instinctual. He's a very good tackler. It may end up being that it fits all the things he's good at. It could be a home run. His issue is staying healthy. And then when you think about that and all the games that he's missed due to an array of injuries, you start to wonder, 'Ok, if they're committed to this defense, what happens if Jimmie Ward misses six games? Who lines up there then?' That's another offseason mystery problem that this team has to solve."

Barrows was asked if Ward can be that type of intimidating safety, much like Thomas from Seattle. What would Ward's role be on the 49ers' new-style defense?

"I think he has that attitude," Barrows said. "I mean, he's not afraid to hit. The question is: At 195 pounds, should he be afraid to hit (and) throw his body around? He's the last line of defense. He's the guy, if you're not a good tackler, then you've got a problem back there because, like I said, if you get past him, there's only a lot of green grass between you and the end zone.

"I think he's a good tackler. He's not the Kam Chancellor guy. He's not the guy who's going to be thumping 255-pound tight ends. They don't want him doing that. But I think he's good to very good at tackling for what he is – a free safety."

Barrows was asked about former 49ers safeties like Dashon Goldson and Donte Whitner, who were known as strong hitters on the defense.

"His hammer is not Dashon Goldson's," Barrows said. "It's not Donte Whitner's. But you could make the argument that those two guys weren't awesome in pass coverage either. That they were much better as thumpers than they were as center fielders."

You can listen to the entire interview on KNBR.

Like so many other 49ers players, Ward ended the 2016 season on injured reserve following a shoulder injury suffered during a December matchup against the Atlanta Falcons.