The most improved rookie on the 49ers through five games

It's not who you think.

San Francisco 49ers head coach Kyle Shanahan. | Darren Yamashita-Imagn Images

The most improved rookie on the 49ers through five games has not been first-round pick Mykel Williams, nor has it been third-round pick Upton Stout, even though both have played well.

Those two were impressive in training camp and remain impressive today. But this rookie may have surpassed both Williams and Stout, which is remarkable, considering how bad this rookie was in training camp.

I'm talking about second-round pick Alfred Collins.

How much Alfred Collins has improved since July

San Francisco 49ers defensive tackle Alfred Collins (95). | Darren Yamashita-Imagn Images

Collins missed all of OTAs and minicamp with a calf injury, plus he hadn't signed his contract yet. So when he finally showed up for training camp, he was out of shape. He had to lose roughly 40 pounds, and he had to learn how to play in an attacking-style 4-3 defense, considering he played in a passive read-and-react 3-4 defense in college.

In the one-on-one pass-rush drills in camp, he was arguably the worst defensive tackle on the field. He would pop straight up, get blocked, and then stop before the whistle.

Now, he's in terrific shape, he's defending the run like the 49ers hoped he would when they drafted him, and he's becoming an actual playmaker. During the 49ers' most recent win over the Rams, he played a whopping 40 snaps on defense, hit Matthew Stafford once, forced a fumble at the goal line, and recovered the fumble himself.

It was one of the best plays anyone has made in the NFL this season. Collins literally saved the game for the 49ers after starting defensive tackle Kalia Davis went down with a broken hand.

San Francisco 49ers defensive tackle Alfred Collins (95) forces a fumble by Los Angeles Rams running back Kyren Williams (23) at the 1-yard line in the fourth quarter at SoFi Stadium. | Kirby Lee-Imagn Images

Mykel Williams has been solid against the run and has made some impressive tackles for loss, but he hasn't won a game for the 49ers yet. His improvement has been gradual.

Upton Stout did help seal the victory over the Arizona Cardinals with a clutch pass breakup on the final defensive play.

But against the Rams, Stout got targeted 8 times and gave up 7 catches for 86 yards and a passer rating of 111.5 before eventually leaving the game with an ankle injury and getting replaced by Chase Lucas. So Stout's improvement has been up and down.

Meanwhile, Nick Martin, Jordan Watkins, Jordan James and Kurtis Rourke still haven't played, CJ West has been underwhelming, Marques Sigle is starting but on the verge of getting benched for Malik Mustapha as soon as he's ready to play, and Connor Colby is starting until Ben Bartch returns from a high ankle sprain.

Who would have thought in July that Collins would be better than all of these rookies?

Probably not the 49ers.