The 49ers' Biggest Remaining Need as they Begin OTAs

This offseason, the 49ers said they wanted to get better in the trenches. That's why they spent three of their first five draft picks on defensive linemen.

But in retrospect, the 49ers didn't really address their trenches. They addressed a trench. Singular. The other trench yet again got the short end of the stick.

The offensive line remains the weakest position on the 49ers. This year, they spent a seventh-round pick on Connor Colby, a guard, and signed D.J. Humphries, a veteran tackle coming off a torn ACL.

That's why Pro Football Focus says the offensive line, particularly the interior, is the 49ers' biggest remaining need.

"The 49ers did little to add depth or new faces to their offensive line group, specifically on the interior," writes PFF analyst Trevor Sikkema. "They have a gem in Dominick Puni, who was a fantastic starter as a rookie last season, earning an 81.9 PFF overall grade. But Jake Brendel recorded a 67.9 mark at center, and with Aaron Banks gone, Ben Bartch will have to step up at the other guard spot as things stand."

Bartch has had trouble staying healthy in the NFL, so I'm guessing the 49ers will platoon him and Spencer Burford at left guard, meaning the two of them will take turns. Early in Burford's career, he platooned with Daniel Brunskill at right guard, so he's no stranger to a timeshare.

But a Burford-Bartch platoon still isn't as good as Banks. The 49ers offensive line could be an issue all season. Expect the 49ers finally to address it next year. They have no choice.