This is the San Francisco 49ers' biggest concern on defense by far

This defense doesn't have many concerns right now, but this is one.

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The San Francisco 49ers' defense has been a pleasant surprise this season. The team has been leaning on its youth to push them over the top, and in most cases, that has been working. However, one player who has stalled out in their progress so far is Renardo Green.

Do the San Francisco 49ers have an issue with Renardo Green?

Green is a second-year player after being a former second-round pick. He came along as the season went on and started to earn a starting spot. By the end of the season, he was playing so well that the team was comfortable starting him in 2025 with limited depth to compete. Through three weeks, he has not been the same player as in his rookie season. 

Green has given up far too many big plays. Jaxon Smith-Njigba and Rasheen Shahid burned him in the first two weeks. He was good in moments against the Cardinals, but had two major gaffes in Week 3. 

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When the 49ers went up 13-6, the Cardinals promptly marched right down the field to tie the game. The first big play was a 32-yard reception to Marvin Harrison Jr. Pro Football Focus attributed the catch to Fred Warner in coverage, and that is because he was in zone. 

However, it looks like Green was in man coverage with his receiver, and the zone that Kyler Murray led Harrison to was the zone crossing from Warner to where you would assume Green would be. It looks more like an issue with the cornerback and not the All-Pro linebacker. 

Just a few plays later, Green was charged with pass interference in the end zone, another gain of over 30 yards for the Cardinals. Green once again looked confused in his assignment. He lost his man, tried to make up ground too fast, and did not play the ball, resulting in the penalty.

Neither pass shows up in the box score as a mark against Green, but it is clear that his side was being picked on when the Cardinals needed to score late. This has been the case for three straight weeks now as well. 

The 49ers are a bit thin at cornerback, and it is hard to see them benching Green at this point. The second-year player simply needs to play better, though. San Francisco has seen this from him before, and if he does start to perform better, this defense could take another big step.