Grading every 49ers rookie performance in their preseason debuts

Saturday night was the first time the San Francisco 49ers rookies got a taste of NFL game action.

The results were a mixed bag among the rookies who played.

San Francisco had 17 rookies on its roster going into the preseason opener.

Of those 17, 13 played against the Denver Broncos and gave us something to work with in evaluating their overall performance in preparing for their first NFL seasons.

We went through and offered a grade for each 49ers rookie after their preseason opener:DE Mykel WilliamsHe was inactive due to a knee injury.

There's some optimism that he won't miss much time and we may see him in Week 2 of the preseason when the 49ers visit the Las Vegas Raiders.Grade: IncompleteDT Alfred CollinsIt was not a good debut for the 2025 second-round pick.

Collins didn't start and played 25 total snaps.

The problem for the big defensive tackle is that he was virtually invisible.

He didn't make a significant impact on any play as a run defender or as a pass rusher.

The pass rush is expected to take some time to develop, but his inability to affect the run game out of the gate is definitely a concern.Grade: D-LB Nick MartinThere was one big stick from Martin on a swing pass on a second-and-12 that brought up a third-and-12.

Outside of that his most memorable plays include two missed tackles on plays that went for 18 and 16 yards.

He also whiffed an open field tackle on a long third down conversion that was negated by a penalty.

Martin was also late to diagnose a play in the red zone that led to a Broncos touchdown.

It wasn't a strong night for the third-round pick.Grade: FCB Upton StoutIt looked initially like Stout had sewn up a starting job when he didn't suit up Saturday night.

Head coach Kyle Shanahan after the game said Stout has a calf injury.

He's still the likely frontrunner for the nickel cornerback job.

It was disappointing not getting to see him in games after his strong showings in practice.Grade: IncompleteDT CJ WestThe 49ers are probably happier with West's game than they were with Collins's.

The fourth-round pick did well to split a double team to blow up a run, and another time he took on a double team to free up fellow defensive tackle Kalia Davis for a run at the quarterback.

Ideally he'd have been more productive, but there were enough flashes to be optimistic about him going into the second preseason game.Grade: C+WR Jordan WatkinsWatkins was the winner of the night among the 2025 draftees.

He caught three of his six targets for 56 yards, including a 50-yard over-the-shoulder grab on a sweet throw from Mac Jones to set up the 49ers only touchdown of the game.

He got targets in all three levels of the passing game with another two behind the line of scrimmage.

There's a chance Watkins sees real playing time early with injuries ahead of him in the receiving corps.

Grade: A-RB Jordan JamesA broken finger that required surgery will likely keep James out of the preseason altogether.Grade: IncompleteS Marques SigleIt wouldn't be a surprise to see Sigle sneak his way into the starting lineup at some point.

There's uncertainty in the back of the 49ers' secondary and Sigle had a nice preseason debut.

He racked up six tackles and didn't allow a reception in coverage.

His athleticism is apparent with how often he was around the football.

It was an overall strong debut for the fifth-round pick.Grade: A-QB Kurtis RourkeRourke is still on the non-football injury list because he had a torn ACL repaired.

He may not make it off the injured list this season.

Grade: IncompleteOL Connor ColbyIt wouldn't be a shock to see the seventh-round guard from Iowa make the 53-man roster.

He was perfect in 21 pass blocking opportunities Saturday according to Pro Football Focus.

With a rough overall performance from the offensive line there are plenty of opportunities for a young player like Colby to move up.

Grade: B+WR Junior BergenExpectations were high for Bergen as a punt returner and he didn't disappoint.

It wasn't an awesome night as a receiver for the rookie from the University of Montana.

He had a drop and no catches on two targets.

He did rip off a 28-yard punt return, though, on his first opportunity.

Bergen made a defender miss with a nifty move before finding the corner to help flip field position.

Punt returns are going to be his way to a roster spot so the big return is a good sign for him.Grade: C+RB Corey KinerKiner had an impressive debut where he rushed for 45 yards on 10 attempts.

He ran hard and showed off good vision and balance in his team-high 10 carries.

With James working through an injury, there's a wide open door for Kiner to push his way onto the 53-man roster.Grade: AOL Drew MossThe undrafted rookie offensive lineman put together a strong debut, not unlike Colby his fellow rookie interior offensive lineman.

PFF had him down for no pressures in 14 pass blocking opportunities.

Moss may be practice squad bound, but it was a good first game for him.

Grade: ACB Jakob RobinsonReports out of the SAP Performance Facility have been complimentary of the undrafted rookie from BYU.

He did a nice job of staying sticky in coverage and ensuring receivers didn't get run-after-catch opportunities.

It was a good night all around for the 49ers' secondary so Robinson may be a practice squad candidate, but he's paving a positive path in his first NFL preseason.Grade: CDL Sebastian ValdezIt was impossible not to notice Valdez.

His strength was extremely clear and he was a frequent visitor to the Broncos backfield.

He had a sack and with openings on the defensive interior, Valdez may have the best shot among the undrafted players to make the team and see significant action as a rookie.Grade: A-LB Stone BlantonBlanton had an up-and-down debut where he showed off good instincts and a potential NFL skill set.

He also missed some tackles and looked a step behind a few times.

It wasn't perfect, but we're intrigued to see him over the next couple preseason games.

Grade: CS Derrick CanteenCanteen played a lot with 66 total snaps.

He lined up all over the field and showed off a willingness to stick his nose in and hit.

With injuries in the secondary, Canteen is a name to keep an eye on throughout the rest of the preseason.Grade: B-This article originally appeared on Niners Wire: 49ers rookie grades from NFL preseason debut vs.

Denver Broncos.

This article has been shared from the original article on yahoo, here is the link to the original article.