Amidst the fast-paced world of the NFL, rising stars can make their move out of the pack overnight if the right opportunity is provided. 49ers rookie safety became a beneficiary of that opportunity after making early impressions during training camp and the preseason, and Kyle Shanahan is keeping close tabs on the young defensive back. With Mustapha out of commission, the 49ers turned to their rookie to fill a starting spot, a testing ground that would show his preparation and composure at the professional level.

Shanahan was upbeat in his assessment of Marques Sigle after the 49ers’ season-opening 17-13 win over the Seattle Seahawks. “Since training camp, he’s jumped off the practice field. He did well in the preseason games. We had a feeling about this guy from the first week in camp. We were hoping he’d be that way, studying him at Kansas State. He came in and looked that way really early and continued that way. I was just hoping he would look that way in the game, and he did,” Shanahan said on NBC Sports. The coach’s claim validates the trust in Sigle’s preparedness, confirming that his game was no fluke but the result of perseverance and commitment in training since college.

Sigle’s preseason figures justified Shanahan’s optimism and demand that he replicate his college plays. He tallied 14 tackles in his three games and even demonstrated play-reading skills and right-place skills, which many take years to learn in this league. He made seven tackles in the preseason opener against the Broncos, three in a close victory over the Raiders, and four against the Chargers, and demonstrated his physicality and ability to read the play. All those moves made Shanahan think that Sigle was ready to start the process of opening up Week 1 against a solid Seattle side.

The rookie also had a strong college foundation. A fifth-round selection of the 2025 NFL Draft, Sigle played in 50 games during five seasons at Kansas State and North Dakota State and posted 174 tackles, 10.5 TFLs, 7 interceptions, and 26 pass deflections. Sigle started 13 games for Kansas State in 2024 and recorded 60 tackles, 3 interceptions, and 6 pass deflections, of which one was turned into a touchdown. Sigle’s versatility to play and being consistent made him an ideal player to step in place of Mustapha without skipping a beat.

Kyle Shanahan opens doors for Marques Sigle following Malik Mustapha’s injury

49ers starting safety and 2024 prospect Malik Mustapha has been placed on the reserve/PUP list due to a knee injury, forcing San Francisco to work through their secondary. The injury came as a result of an initial ACL tear he experienced at Wake Forest, which he had surgery on last season. Mustapha’s rehab schedule will have him missing at least the first four games of the season. And there will be a desperate need for some quality depth at the position, as he’s been on the sidelines after week 17 from last season.

During 2024, he had 72 tackles, out of which 32 were solo, five pass breakups, and one interception in 16 games (12 starts). He was a physical, reliable force in the 49ers’ secondary, and his temporary loss is an opportunity for Sigle a chance to shine at the NFL level.

The 49ers signed New York Giants free safety Jason Pinnock as a temporary stopgap. Pinnock sees NFL action entering the field as a rotational starter and defender. But coaches clearly favor Sigle more as the temporary answer for filling the second level. As Kyle Shanahan had made it clear, the rookie’s camp showed readiness. And his college exploits all played a part in the decision to defer to him in Mustapha’s absence.