49ers making plans at linebacker without Dre Greenlaw

SANTA CLARA — There’s an air of mystery for the 49ers regarding the statuses of Trent Williams and Brandon Aiyuk. Maybe they’ll work out their contract issues and get on the field soon, maybe not.

There is no such drama at linebacker, where they realize Dre Greenlaw is destined to be a spectator for a minimum of four weeks as he rehabs his torn Achilles in Super Bowl LVIII. And that’s the best-case scenario.

It’s no small thing. Greenlaw has been the trusted sidekick to All-Pro Fred...