San Francisco 49ers: Grading each position heading into 2018 training camp

Key Additions: Mike McGlinchey, Weston Richburg, Jonathan Cooper

Key Departures: Trent Brown, Daniel Kilgore, Brandon Fusco

Perhaps no other unit went through as massive a change as the 49ers offensive line this offseason.

Only one Week 1 starter from last year, left tackle Joe Staley, remains on the roster. The team changed out center Daniel Kilgore in favor of Weston Richburg, signed in free agency, and made a similar move by trading right tackle Trent Brown after selecting Notre Dame’s Mike McGlinchey in Round 1 of the NFL Draft.

Richburg fills a key void in head coach Kyle Shanahan’s O-line. But Richburg is also coming off a concussion injury last season that limited him to just four games. That’s something of a gamble.

Yet the biggest question mark is at the guard positions, where three players — Jonathan Cooper, Laken Tomlinson and Joshua Garnett — are vying for two starting jobs.

Tomlinson, who just received a three-year extension, is all but a lock to start in 2018. But Cooper is coming off an MCL injury, while Garnett missed all of 2017 with a knee issue.

It’s anyone’s guess who wins out the other job. But since there are so many new faces within this unit, it’s going to be hard to gauge how effective the O-line will be until the pads come on in July.

Until then, a C-plus grade is warranted.