The 49ers have to figure out what to do at weakside linebacker.

They could re-sign Dre Greenlaw who will turn 28 in May and missed all but 34 snaps last season due to injuries. They could draft a linebacker. Or they could sign one of the top linebackers in free agency such as Nick Bolton of the Kansas City Chiefs.

Pro Football Network expects the 49ers to choose Option C — sign Bolton.

“It is intriguing to put a player like Nick Bolton next to Fred Warner.” writes PFN analyst Ben Rolfe. “Bolton was the centerpiece of the Chiefs’ defense and has the chance to be Warner’s long-term partner in the center of the 49ers defense. We have seen that the 49ers place a high importance on the position and Bolton could be the next evolution of that.

“Bolton has three 100-tackle seasons in his first four years and has also proven a nuisance around the quarterback. He is a versatile piece that feels like a luxury for the 49ers, but he can get after the passer or drop into coverage. The thought of Warner and Bolton together in a defense will be terrifying for opposing offenses.”

Rolfe is correct that the 49ers highly value the weakside linebacker position. Once, they spent a first-round pick on Reuben Foster. And when he didn’t work out, they signed Kwon Alexander to a four-year, $54 million contract.

Don’t be surprised if the 49ers offer Bolton a similar deal. Robert Saleh was the 49ers defensive coordinator when they drafted Foster and signed Alexander, and he’s a former linebackers coach. He won’t allow the 49ers to have a weak linebacking corps for the second season in a row.