The 49ers have been as “aggressively prudent” as general manager John Lynch said the team would be in free agency. The team elected to sign non-marquee players that fit head coach Kyle Shanahan’s scheme rather than pay for the most expensive options. They wasted little time signing an immediate upgrade along the interior offensive line.

Franchise quarterback Jimmy Garoppolo showed he can elevate the play of those around him, leaving interior offensive line a critical priority to help protect him. Weston Richburg, who the team signed as a free agent this week away from the New York Giants, will immediately step in as a leader up front. He’s smart, technically proficient and has been trained by offensive line guru LeCharles Bentley. But he’s far from the only upgrade needed. After signing Richburg, the team traded veteran center Daniel Kilgore, leaving the need for depth still apparent.

The team is hoping former first-round pick Joshua Garnett has been able to makeover his body to fit Shanahan’s scheme, but that’s far from a lock. Interior offensive line help is still a need with the draft just over a month away. Let’s look at the potential guards that could fit alongside Richburg up front.

Top-Tier: Austin Corbett (6-4, 306) | Nevada

Corbett has been a steady riser since moving inside to guard at the Senior Bowl. He was asked by teams to take snaps at center and played all over the line in an impressive showing. After walking on at Nevada, Corbett started all four years at tackle and demonstrated a smooth pass set.

(Troy Taormina-USA TODAY Sports)

He has the size and strength of a starting-caliber guard. Corbett wins with a well-timed punch and football intelligence. He understands angles as a second-level blocker and plays well in space. The 49ers could grab Corbett at the back end of Round 2 and have a starting guard immediately.