There's been a lot of excitement about Larry Borom, so I decided to rewatch the 49ers game, focusing exclusively on him. I thought I'd share my observations, in case anyone is interested.
Borom was generally able to handle Bosa one on one. Gave up some pressure (and a couple more that would have been pressure if Fields had held the ball longer), but always at least slowed his guy down. Probably his worst pass blocking rep came at 2:54 in the third. Bosa beat him inside, but Borom got in his way enough to let Fields take off. Unfortunately, he ran into someone else and didn't end up making it back to the line of scrimmage.
I counted 16 pass/scramble plays where Borom was singled up on Bosa. 12 of those were in the first half. Kmet started giving him more help in the second half, but one time that actually contributed to a sack. At 5:06 in the fourth, Kmet was supposed to chip Bosa and then leak out into the flat. He got tangled up with Bosa, so he was late releasing. Meanwhile, Borom was just sitting around, waiting to block Bosa after the chip. Fields rolled out to his side, so I'm sure if Kmet had been on time, Fields would have found him instead of getting sacked.
Borom showed good awareness picking up stunts, other than one time (2:15 in the third) where he engaged Bosa initially, but Bosa was stunting, so Borom passed Bosa off to Daniels and went to block 91, who was looping around. But Borom disengaged just a smidge early, so Daniels struggled with Bosa.
When asked to run block the guy in front of him, Borom was not dominant, but he always looked competent. He didn't always hold his blocks long enough, however. A good example was at 11:04 in the fourth, Borom was blocking 91 but let him disengage too easily and make the tackle.
When asked to make a reach block, he was ineffective. For example, at 9:27 in the second, 93 was lined up over Borom. It appeared that Borom was supposed to go left and push 93 to the right, but he ended up just sort of pushing 93 weakly, and he ended up working down the line and getting involved in the tackle.
When asked to work to the second level, he was the John Travolta meme from Pulp Fiction. A good example of this was at 12:54 in the second. Borom kind of put his hand in Kmet's back while Kmet was blocking Bosa, then ran a few yards downfield and waved at 36, who ignored him and made the tackle.
This all might sound a little negative, because I'm picking the worst reps to describe. That's just due to the nature of offensive line play. If one guy gets a pancake, but the guy next to him whiffs, your play is blown up. So whereas in skill positions you're looking for explosive plays, for OL you're looking for the guy where you can live with his worst plays. For Borom, I say so far, so good.