It wasn’t a large undrafted free agent class for the Pittsburgh Steelers — frankly, it never is — but the Steelers landed some rather intriguing pieces following the conclusion of the 2025 NFL Draft. They added seven players via undrafted free agency, including two rather intriguing wide receivers, an uber-athletic tight end and a small-school offensive lineman who brings real intrigue.
But there’s one Steelers undrafted free agent signing that has drawn the most attention and has been universally praised. That would be Iowa safety Sebastian Castro.
After going undrafted, Castro decided to stick in the Black and Gold, signing with the Steelers, giving him a shot to compete for a roster or practice squad spot as that versatile safety who can play in the box or in the slot.
For The Athletic’s Nick Baumgardner, Castro is the Steelers’ best UDFA signing. In a piece for The Athletic, Baumgardner highlighted the best UDFA signing for all 32 teams, and Castro’s move for the Steelers was easy for Baumgardner.
“A three-year starting safety — and a playmaker — for Phil Parker’s always-tough Iowa defense, Castro doesn’t have elite athleticism but is an extremely smart defender, both in pass coverage (especially zone) and run support,” Baumgardner writes.
With the experience and production Castro had at Iowa as a three-year starter, it seemed likely he was going to be drafted. But below-average testing numbers at the position — 4.59 40-yard dash, 9’9″ broad jump, 30.5-inch vertical — caused him to fall out of the draft.
Still, Castro brings a relentless motor to the table and flies around all over the field, making plays. He’s stepping into a safety room that is seemingly locked up with Minkah Fitzpatrick, DeShon Elliott, Juan Thornhill and Miles Killebrew, but Castro has the chance to surprise and work his way into a role due to his versatility and ability to play in the slot.
At cornerback, Beanie Bishop Jr., rookie Donte Kent, and even veteran free agent signing Brandin Echols have slot abilities, though the Steelers could use some help there.
There’s a path for Castro, but he has to make plays immediately and stand out.
Steelers Depot’s Jim Hester had this to say about Castro in a pre-draft scouting report.
“Slot cornerback is an underrated and important position in the NFL, and Castro will probably make his home there for the most part but does have good experience that can allow for defensive coordinators to use him as a chess piece. Castro will need to work on his jamming technique in press, not being too overaggressive as a run defender, and not riding receiver’s hips too closely leaving him open for moves to occur and throw his balance off creating separation.”
Hester gave Castro a fourth-round grade. He ultimately went undrafted, but that doesn’t mean he isn’t talented and a good fit within the Steelers’ defense.
He’ll be a name worth following throughout the offseason and in training camp.
