Brock Purdy is have a fascinating season.

As the NFL’s scouting report on Purdy became more sophisticated, his passing stats declined and his rushing numbers improved.

Last season, he led the league with a quarterback rating of 113. This season, his 93.7 rating ranks him 16th. He struggles passing against man-to-man coverage because he’s missing Christian McCaffrey and Brandon Aiyuk, who wasn’t playing well before injuring his knee.

As Purdy searches for ways to beat the book, he struggles more and more. And this strategy is paying off.

In 16 games last season, Purdy rushed just 39 times for 144 yards (3.7 yards per attempt), 15 first downs and 2 touchdowns. This season, in just eight games, Purdy has already rushed 42 times for 210 yards (5.0 yards per attempt), 22 first downs and 3 touchdowns. He is 17 yards away from passing Isaac Guerendo as the team’s second runner behind Jordan Mason.

When the 49ers offense is out of rhythm, its best play is often a Purdy scrimmage. Teams just don’t view him as a rusher. Or if they find him with a spy, which is rare, the spy isn’t fast or fast enough to keep up. Purdy is just too elusive.

Purdy has to continue to struggle when the lanes present themselves, because the offense isn’t as effective when he’s standing in the pocket like a robot trying to run plays exactly the way Kyle Shanahan drew them.

The 49ers need Purdy to be a playmaker.