ET's Lauren Zima spoke to the Bachelor in Paradise host on Monday, and he threw in his two cents about which franchise alums would be successful on Dancing With the Stars. While Harrison had high hopes for recent Bachelorette Hannah Brown, he wasn't so optimistic about Underwood's chances
"If Hannah's on, she'd be great. Colton I don't think would be great," Harrison told ET.
Despite thinking that Underwood is "awesome," Harrison said the former NFL player would have to "take his shirt off on day one and use his unbelievable charm and charisma and personality" to compete on DWTS.
"I love Colton. He's like my little brother. He's not a good dancer," Harrison said of Underwood, who chose Cassie Randolph at the end of his season of The Bachelor. "... He has no rhythm at all. That doesn't come to you."
Though he's uncertain about Underwood's dancing abilities, Harrison confirmed that the 27-year-old reality star would make for "great TV."
"He'll go far 'cause, here's the thing with Colton, he is a ridiculous athlete, obviously, he's a world-class athlete, and he grinds and he will try," Harrison said. "He will put in the effort, but I'm talking he's at zero, he might get a two if he crushes it. Whereas Hannah is a performer. I think she can dance. She'll be at a four [and] can get up to an eight."
If there happened to be a showdown between Brown and Underwood, Harrison said he'd put his money on Brown to walk away with the Mirrorball Trophy.
"Athletes have a great history on the show, but usually it's the athletes that are good at dancing," Harrison said. "... I'm going to say Hannah would have a better chance at winning just because... we love Colton, people are going to vote for Colton because of that, he'll be shirtless with puppies and stuff... but I don't think he can go all the way."
"Why isn't it Tyler [on Dancing With the Stars]?" he said. "Tyler dances. He had the whole Footloose thing!"
When asked if he'd ever compete on the dancing reality show, Harrison quickly shut down the idea. "Why would I?" he said, before jokingly adding that he has "skills."
Bachelor in Paradise's sixth season premieres Monday at 8 p.m. ET/PT on ABC, and will air Mondays and Tuesdays on the network. Join ET's Bachelor Nation Facebook group here.