Mike McGlinchey is no stranger to pressure. The man dubbed the "CEO" by teammates has been under pressure to perform ever since he was drafted ninth overall in the 2018 draft and the 49ers promptly traded away incumbent RT Trent Brown. Brown is good in pass protection and solid in the run game as his sheer size can overwhelm opposing DEs. But he didn't offer the mobility in the running game that Shanahan was after for his outside zone scheme, so the 49ers decided to move on and replace him with a rookie first rounder in McGlinchey, despite having a number of other holes on the roster they could have addressed at that pick.
From a running game perspective, the decision to replace Brown with McGlinchey has been a huge success and paid immediate dividends. In 2017 the 49ers ran for 1,662 yards at an average of 4.1 yards per carry. This increased to 1,902 rushing yards in 2018 at 4.5 yards per carry, and then exploded for 2,305 yards at 4.6 yards per carry in 2019 (regular season only). In 2020 the rushing statistics regressed some to 1,889 yards and 4.3 yards per carry, though injuries played a considerable part in that.
And Mike McGlinchey played a significant role in the increase in rushing yards and the success of the 49ers ground game. Directional rushing statistics courtesy of Sharp Football Stats outlines the following yards per carry for the 49ers rushing to the right side since 2017:
2017: 4.2 (yards per carry) behind RG, 3.1 behind RT, 3.3 outside RT
2018: 2.8 behind RG, 4.7 behind RT, 5.8 outside RT
2019: 3.2 behind RG, 6.7 behind RT, 5.8 outside RT
2020: 4.9 behind RG, 4.3 behind RT, 7.4 outside RT
The 49ers success running behind or outside the RT increased significantly following the transition from Brown to McGlinchey. While part of this also comes down to the supporting cast, there is little doubt that McGlinchey has proven himself to be an excellent run blocking RT and one of the best run blocking OTs in the NFL over the past three seasons.
However, despite McGlinchey's success as a run blocker, he has found less success in the passing game. While different services will likely give different statistics and grades for individual OL, McGlinchey has been credited with approximately 5 sacks in each of his three seasons and around 35 to 40 pressures allowed each season. And according to PFF (which is admittedly a questionable grading system), his pass blocking grades the past three season have been 64.2 in 2018, 67.1 in 2019 and 58.3 last season.
As a pass blocker, McGlinchey has been a downgrade from what Trent Brown provided. And with the passing game now widely considered across the league to be critical to team success, pass blocking is generally considered to be more important than run blocking (though given the way Shanahan runs his scheme it would appear the 49ers do not follow this line of thought).
Of concern, McGlinchey has not shown consistent signs of improving as a pass blocker. In fact, after a marginal improvement in 2019, his pass blocking appeared to regress in 2020.
Part of the reason for this regression may have been weight related. When McGlinchey arrived at camp last offseason many people noted how much weight it appeared McGlinchey had lost. The "CEO" had transformed into the "Big Slim", as Richard Sherman labelled him, and according to McGlinchey himself he was under 300lbs last season. The idea behind the weight loss was to improve his fit within the outside zone scheme, by increasing his mobility. He may have been correct about the fit within the running game - as outlined above the team's yards per carry outside the RT were the highest in the Shanahan era and McGlinchey earned his highest ever run blocking grade from PFF.
However, it caused a number of issues in pass protection. "Big Slim" struggled to anchor against the bull rush all season, finding himself on skates numerous times and on his backside on more than one occasion. Being thrown to the ground by DEs is never a good look for an OT, and when it happens repeatedly there is a problem. The problem was exacerbated when he was unable to set his feet before the defender got into his body, as he didn't have the weight behind him to stall the rush, re-establish his balance and drop anchor. To compensate, over the course of the season McGlinchey started to set his feet too early in anticipation of the bull rush only to then be beaten around the edge by speed or counter moves. All in all, it was a torrid affair for McGlinchey in pass protection all season long as he was unable to find consistency.
At the end of the season both John Lynch and Kyle Shanahan noted McGlinchey's weight was a concern and may have contributed to his struggles in the passing game, and that they would discuss with McGlinchey his "ideal" weight for 2021. McGlinchey appeared to resist the idea directly after the season, indicating his weight was not the issue. However, based on pictures of the players at the current camp activities it would seem McGlinchey has taken the guidance on board as he looks noticeably heavier.
The 49ers showed faith in McGlinchey this offseason, picking up his fifth year option after the draft. To repay that faith it will be important for McGlinchey to start showing signs of improvement in pass protection while continuing to excel in the running game. And there is a possibility that if he doesn't improve in pass protection his weakness will be magnified. Last season his poor play in pass protection was somewhat hidden by the even worse play at center and RG. This offseason the 49ers have brought in Alex Mack, Aaron Banks and Jaylon Moore, which should significantly improve the interior of the OL and put more pressure on McGlinchey to hold up his end of the line.
If McGlinchey lifts his game in pass protection there is a real possibility the 49ers offensive line could be one of the best units in the NFL this season, which would go a long way to the 49ers returning to a dominant rushing attack like we saw in 2019 and keep the 49ers QB clean to take advantage of the opportunities Shanahan can scheme up.
The pressure's on, Mike.