The Englishman, who has played on three winning teams in the biennial event, delivered his observation after playing with MacIntyre for the first time in the final round of the Omega Dubai Desert Classic.
Casey came out on top to land his 15th European Tour title, but the 43-year-old admitted he’d become the latest member of MacIntyre’s growing fan club.
“Great player,” he said of the 24-year-old Scot. “He's got a very strong possibility of being on Paddy's Ryder Cup team come later this year. He was brilliant.
“He's got a good demeanor, very good demeanor. Look, I couldn't really see a weakness there. Great attitude. He's a good ball-striker. A lot of good attributes, good player. He's got a good brain.”
European captain Padraig Harrington delivered a glowing assessment of MacIntyre as Ryder Cup contender earlier in the week, though hinted that he probably needs to secure one of his nine automatic spots for the rescheduled event.
“You know, I'd feel very comfortable standing next to him on a first tee at Whistling Straits,” added Casey, who was handed the job of partnering Tyrrell Hatton on his debut in France in 2018. “He’s pretty fearless and, you know, he's only going to get better and better and better.
“He was great to play with, and you can't always say that about guys. Actually, if anything, he helped me. So thanks, Bob.”
Casey could climb to 14th from 27th in the world rankings after landing his 20th worldwide win, having made his breakthrough in the 2001 Gleneagles Scottish PGA Championship.
“Last year was just rubbish,” he said of the world being hit by Covid-19. “I didn't enjoy my golf in 2020. I mean, I played well one week but that was about it. So this is really cool.”
On his own hopes of playing in the Ryder Cup, Casey admitted: “Paris was the greatest golfing experience I've ever had.
“I would love to be part of this team, and if I'm not playing, I'd still love to be part of that team and help."