Not since 1966 had the Steelers parted with a first-round draft selection, and if they were going to do so for Fitzpatrick, they had to believe that the team, led by a backup quarterback, would finish well enough that its pick would fall late in the round, or at least not in the top 10. Otherwise, following a poor season and with their quarterback situation in flux, they would be squandering a prime opportunity to draft Roethlisberger’s successor.

“We end up with our No. 1 being 20th or 25th again, we probably made a good trade,” defensive coordinator Keith Butler said. “I thought we made a good trade anyway, regardless of where we land. I’m glad we got him.”

Coach Mike Tomlin added in an interview, “It really wasn’t a hard decision on our part.”

Tomlin scouted Fitzpatrick twice before the 2018 draft — just in case, Tomlin figured — even though he knew he would be gone when Pittsburgh picked at No. 28. He liked Fitzpatrick’s awareness and his ball skills, communication style and personality. Tomlin said he also valued the versatility that allowed Fitzpatrick to practice at six positions in Miami, though he intends to keep him at free safety, at least for now.

Before Fitzpatrick had practiced with the Steelers, Tomlin announced that he would start that week at San Francisco. The team accommodated Fitzpatrick by simplifying his assignments, giving him a menu of defenses it expected to run so he could relate them to those from his previous schemes. Every week the Steelers have layered on more responsibilities, and Fitzpatrick has conquered them all.

“For a guy who’s only been on the defense for a few weeks still,” outside linebacker T.J. Watt said, “he’s communicating like he’s been in this defense his whole life.”

The Steelers have a rich history of outstanding defensive backs, from Mel Blount to Rod Woodson, Mike Wagner to Donnie Shell. But they haven’t had a player with Fitzpatrick’s acumen and athleticism since Troy Polamalu, curly locks flowing from beneath his helmet, last patrolled the secondary in 2014. Butler said it was too early, and unfair, to compare Fitzpatrick, in his second season, to Polamalu, a former defensive player of the year who’s most likely headed to the Pro Football Hall of Fame.