Football is the ultimate team sport, which is one of the things that makes it so special. It’s incredibly uncommon for a single player, with the exception of the quarterback position, to entirely transform the fortunes of an organization for the better. How frequently can the hiring of a single non-quarterback be cited as a definitive turning point for an entire team?

On April 25, 2019, the 49ers selected Nick Bosa from Ohio State with the second overall choice in the draft. Choosing Bosa felt like a home run at the time because he had been a highly anticipated prospect for years and probably would have gone first overall if the Cardinals had actually selected him.

Let’s look at where the 49ers went in the 2019 draft after completing their second season under Kyle Shanahan and the current regime. They were 10-22 in those first two years under Shanahan, with a tremendously underwhelming defense that struggled to get behind the quarterback.

Since Bosa arrived in San Francisco, the 49ers are 39-16 in the 55 games Bosa has started. On the other hand, they’re 15-31 below Shanahan in the games they’ve played without Bosa on the field.

Now, there could be a setback that no matter how talented Bosa might be, he shouldn’t be credited alone for the 30+ percent win rate increase that the 49ers have seen with him in the fold.

Let’s look at one area where Bosa has had a more direct impact, as evidenced by the monumental success the 49ers have had with him on the field. Here’s how the 49ers’ defense ranked under Shanahan before Bosa’s arrival.