Owens has worked out with both players, who will officially become Bulldogs when practice starts next month, but it wasn't anything that happened on the football field that impressed him about Harmon.
"He's athletic for a big guy," Owens said. "We went to go play basketball the other day, and he can move. Guys think we just run into each other but actually we get after it."
Harmon, 6-foot-5, 328 pounds, was rated a four-star prospect by Scout.com and was named a Parade All-American after his senior season at Jefferson County High School. Harmon could end up as an offensive linemen, but he is starting his career playing behind Owens at defensive tackle.
It's too early to say if Harmon will be able to contribute at that position this year, Owens said.
"It's hard to say right now because camp hasn't started," he said. "We just have to see how he adjusts and everything."
Longo, a defensive end, was rated only a three-star prospect and flew under the recruiting radar more than Harmon, but he also has been impressive this summer, Owens said.