Williams, the league's highest-paid offensive lineman, comes in at No. 2, with only David Bakhtiari listed ahead of him.
"After taking a one-year hiatus in 2019, Williams returned to the field for a new squad in 2020 and looked like the same elite player," wrote Anthony Treash. "He notched a 91.8 PFF grade in San Francisco last season, leading all offensive tackles. While his pass protection was strong, it was his performance in Kyle Shanahan's wide zone rushing attack that really solidifies his spot here. Williams earned a career-high 91.8 run-blocking grade and laid down more big-time and positively graded blocks than any other tackle in a season during the PFF era (since 2006)."
Fans and analysts have been quick to criticize McGlinchey's play. While the tackle consistently earns good run-blocking grades from the analytics site, which hit a career-high 91.3 last season, his pass-blocking grade was a career-low 58.3 in 2020 after seeing a slight jump in 2019 to 67.1.
Still, McGlinchey managed to find his way to No. 14 on Pro Football Focus' ranking of tackles.
"McGlinchey ranks this high only because of his elite performance in the run game," wrote Treash. "He underperformed in pass protection in 2020, as has been the case early in his NFL career. A tackle like him can get away with such flaws in Kyle Shanahan's offense, though.
"McGlinchey finished second to only teammate Trent Williams in run-blocking grade among tackles in 2020 (91.3). He finished in the top 10 in both positively and negatively graded run-block rate, something only three other tackles accomplished last year. At the same time, though, McGlinchey ranked fifth-to-last in true pass set grade."
Mack comes in at No. 13 on Pro Football Focus' list of the top 32 NFL centers.
"The only reason Mack isn't higher on this list is age and an expected continuation of decline," wrote Ben Linsey. "There's still no reason he can't be a quality center option for the 49ers still in 2021, even at 35 years old. One of the highest single-season grades of Mack's career came in Kyle Shanahan's final season as the Falcons' offensive coordinator in 2016, including a 90.9 run-blocking grade that led all players at the position. There are few better fits in that scheme than Mack."
Last is Laken Tomlinson, who landed at No. 17 on Pro Football Focus' list of the top 32 NFL guards. Tomlinson has provided incredible value for the 49ers, who traded a fifth-round pick for the offensive lineman in 2017.
Tomlinson has started all 16 games in each of the past three seasons. He earned a career-high overall Pro Football Focus grade of 78.8 last season and a career-high run-blocking grade of 80.9. However, his pass-blocking grade has seen a steady decline, coming in at a career-low 62.2 in 2020.
"A former first-round draft pick who quickly flamed out in Detroit, Tomlinson has gone from strength to strength in San Francisco despite that blocking scheme not necessarily being an obvious fit for his playstyle," wrote Sam Monson. "Tomlinson has allowed three sacks in each of the last two seasons but has thrived as a run-blocker within Shanahan's offense as they incorporate more gap schemes and wrinkles into their outside zone staples."
