The Good and Not So Good about 49ers QB Brock Purdy

Counting the playoffs, Brock Purdy has started 17 games in his career -- that's a full season. Do we know the good and not so good about him yet? Do we know what he does well and not so well?

Patterns have begun to emerge about Purdy.

When the 49ers are rolling, he rolls. When they're winning, he's great. When they're losing, he struggles. He goes as they go.

This season, when the 49ers are winning, Purdy's completion percentage is 69.3, his touchdown-to-interception ratio is 8-0 and his quarterback rating is 120.7. Incredible numbers. And when the 49ers are tied, Purdy's numbers are still great: 74.5 completion percentage, 5-1 TD-to-INT ratio, 122.5 quarterback rating.

But when the 49ers are trailing this season, Purdy's numbers fall off: 63.9 completion percentage, 2-4 TD-to-INT ratio, 82 quarterback rating. That's a stark difference. When the 49ers fall behind and need their quarterback to lead them back, Purdy has failed. Doesn't mean he always will fail in that situation, but he has so far.

And that's because Purdy is a play-action quarterback. When he's winning, opposing defenses have to honor the run, so play action is deadly, and Purdy is a terrific play action quarterback because he can roll left or right and throw. This season, when he's using play action, his completion percentage is 78.4, his TD-to-INT ratio is 8-1 and his quarterback rating is 141.8.

But when he's not using play action this season, his completion percentage is 66.3, his TD-to-INT ratio is 7-4 and his quarterback rating is 98.3. When Purdy has to drop straight back and throw, when there's no run fake or deception, he's not nearly as good.

That doesn't mean Purdy is a fraud -- he's a good player and an excellent fit for what the 49ers do. But elite quarterbacks don't fold when they're behind. We'll see if Purdy can become elite. So far, he's not.