A tweet on Monday lists San Francisco's veteran cornerback, Sherman, and its nickel back as the highest-graded cornerback duo in the league.
Sherman earned Pro Football Focus' highest overall regular-season grade of 88.9 among eligible cornerbacks while Williams' 77.2 overall grade ranked as the eighth-best.
If you include postseason play, Sherman remains at No. 1 with a 90.3 overall grade while Williams jumps up to No. 6 with his mark of 80.3.
Only two cornerbacks allowed a lower passer rating when targeted than Sherman's 46.8. They are J.C. Jackson of the New England Patriots and Tre'Davious White of the Buffalo Bills.
As with most of the cornerbacks on the team, Sherman and Williams are each entering the final year of their deals with San Francisco. Both are scheduled to become unrestricted free agents in 2021.