The San Francisco 49ers may have finally turned the corner with their acquisitions this offseason. After major signings and trades and a successful draft haul by general manager John Lynch and head coach Kyle Shanahan, the team is looking like a severe sleeper in the NFC.

However, many are still skeptical of a team that finished 4-12 and is going into a division with so much improvement across the board. But with injured players like quarterback Jimmy Garoppolo and running back Jerrick McKinnon coming back, they should assist San Francisco in reaching their potential that they were supposed to achieve in 2018. But they still have a few holes to fill before they can get to it.

As many areas of their team improve and make strides, some position groups still need a shot of adrenaline. Spots like the front seven on defense and the positions of running back, receiver, and tight end all improved this year. Quarterback is solidified with Garoppolo returning, and the offensive line looks to be secured with the current group of players they have.

The only group that is under the most scrutiny over lack of depth and talent is the secondary. And it shows with the players.

What needs improvement with the San Francisco 49ers?

Aside from the two interceptions last season (worst in league history), the secondary's woes stretch farther than that. Their best defensive back in 2018 was Richard Sherman with a Pro Football Focus grade of 68.9. Only one other cornerback rated above a 60.0 for the 49ers (K'Waun Williams). But they've answered the questions at this position by signing Jason Verrett and drafting Tim Harris.

Although Verrett has played only five games in the last three years and despite Harris being a seventh-rounder, the team is still improving with these moves at cornerback. But there's one area where the team is again falling behind at and needs help, and it's at free safety.

The team chose to re-sign Jimmie Ward, a player that hasn't played a full season since 2015 and hasn't recorded an interception since 2016. Even worse, is that Adrian Colbert, the guy that took his starting position at free safety, earned a pitiful 31.7 PFF grade in 2018.

Even worse is that Ward went down with a broken collarbone during OTA's. It's something that will likely take him out for eight weeks and give others a chance at the starting free safety position.

But there's an option that the 49ers can explore by signing a safety that's both proven and still available.

Free Agent to Sign: Tre Boston

The six-year pro had more interceptions than the 49ers did all of last year with three in 2018. Boston also has more career interceptions than all of the 49ers safeties combined (six) with his 11 he's put together after five seasons.

And yet, he's still not signed to a team for the 2019 season. It's not too much to be shocked about after he waited until July last year to sign with the Arizona Cardinals for a one-year deal. But he still produced with a 74.1 PFF grade last season and has remained one of the best safeties in the league.

He didn't garner the same type of free agency buzz at his position with the likes of Earl Thomas, Ha Ha Clinton-Dix, and Tyrann Mathieu in the mix, but he's put together significant productivity and shown flashes of playmaking ability with every team he's played for.

It's likely that he will be given another one-year deal from another team this offseason. And why shouldn't it be the San Francisco 49ers? They need all the help they can get in achieving the best defense that they can get to finishing the rebuild. With Boston, they can fulfill that mission with this signing.