That comfort zone also allowed Callahan to switch his brain into receiver mode.
"That's something I've always been doing," said Callahan. "I played little receiver in high school, so receiver isn't something that's foreign to me."
There's a big difference between saying you can do it, trying to teach a corner to do it, and actually being able to do it, Thurmond said.
"You tell a lot of guys to do that, but they can't always process it and can't do it," he said.
"When (Callahan) gets to the ball, he has good ball skills and can make the tough catch. He has the ability to turn a lot of plays that would be pass breakups for other people into interceptions."
Conference USA coaches noticed that ability, too, voting Callahan to the preseason all-conference team. He responded with a big game in the Owls' historic win over Kansas. Callahan picked off two passes, including one that set up Rice's game-winning field goal. The Owls hadn't beaten a Big 12 opponent since the Big 12 was formed in 1996.
Those interceptions gave him eight for his career and pulled him into a tie with three other former Owls for 10th all-time.
"I was overwhelmed with excitement to get our team in position to kick a field goal and win that game," he said.
He's also pretty excited to face the Thundering Herd.
Marshall has completed passes to no fewer than 11 receivers in each of its first three games, so Callahan expects to stay pretty busy Saturday.
"It gives us more to do and gives us corners more opportunities to make plays on the ball," he said. "Marshall has a good, solid offense. They like to throw the ball a lot, so I like that."