Feldman earned the nod over left-hander Brandon Finnegan, who is likely to slot in as the No. 2 starter, Price said.
The Reds signed Feldman on Jan. 26, but he wasn't expected to be the Opening Day starter and wasn't even guaranteed a spot in the rotation. However, injuries to Homer Bailey and Anthony DeSclafani opened the door.
"Baseball is just one of those funny games, you never really know what's going to happen, can't really predict the future, just stay ready for everything," Feldman said. "It's just an honor to get to take the ball on Opening Day and hopefully build off it and have a good season."
Feldman, 34, started Opening Day with the Rangers in 2010 and with the Astros in '14. There have been 51 other pitchers who have started Opening Day for at least three organizations.
"I think his experience and the way he commands the strike zone really puts him as the best candidate," Price said. "Scott is exactly the guy we were looking for and we targeted. Veteran guy with a presence that commands the zone and has a veteran savvy that will serve us well. That will work well in an Opening Day environment."
Feldman was thrilled when he learned Sunday he would be starting Opening Day. It's quite a turnaround for a pitcher who ended last season pitching out of the bullpen with the Blue Jays.
"It's a long ways from pitching relief last year in Toronto to going to be an organization's No. 1 Opening Day starter," Price said. "He's come a long way. He appreciates the opportunity and he's certainly excited about this, as you would think anybody would be. I don't think it ever grows old, it doesn't matter if you're Scott Feldman or Greg Maddux, getting that Opening Day start is a pretty cool thing, I'd imagine."
Feldman has pitched at Great American Ball Park only once before, with the Cubs in 2013.
"Every time it's your first time pitching in a season, it always feels weird," he said. "Whether it's the first day or the fifth day, getting back out there in front of fans and all that kind of stuff, it's always a feeling that generates some jitters and good kind of jitters, though. It's a fun experience."
Feldman has made three starts for Cincinnati in the Cactus League and is 0-1 with a 4.50 ERA and seven strikeouts in eight innings. The 12-year veteran said he's had a good spring, even if it hasn't showed in his stat line.
"[I] feel healthy and like I'm building up strength for the season, and I think the No. 1 thing is just when the season starts to be confident with throwing any pitch in any count," Feldman said. "I feel like I'm on my way toward that."