What happened: The San Francisco 49ers are evaluating rookie offensive lineman Carver Willis as an interior option after drafting the former Washington tackle in the fourth round. Willis is transitioning to guard and center, and the team expects him to sit behind veterans Brett Toth and Robert Jones this offseason.

Why it matters: The transition from college tackle to NFL interior lineman is notoriously difficult, particularly for a rookie adapting to the strength of professional defensive tackles. San Francisco prefers to rely on experienced depth rather than forcing Willis into early action, avoiding a repeat of their struggles with inexperienced linemen last season.

By the numbers: Willis posted a 40-yard dash time in the 78th percentile but recorded a vertical jump in just the 31st percentile. He brings a 6-foot-5, 303-pound frame and started 18 games at right tackle and 10 at left tackle during his collegiate career.

What to watch: Willis will compete for a depth role and attempt to impress the coaching staff during training camp.

Sources