Epstein, appearing on ESPN during Thursday's Cubs-Angels spring training game, reiterated that Bryant might need more seasoning in the minors before making his major league debut.
Bryant, who leads both spring training leagues with nine home runs and is hitting .406 with 15 RBIs this spring, disagrees and thinks he'll be ready on Opening Day.
"I look at it as 'Why not me?' " Bryant said Friday morning. "I think I'm the type of guy that can go out there and do it. I've made it a point of mine to come out here and show them that I can."
Epstein told ESPN on Thursday that he prefers young players to make their debuts in-season, which was his approach with Dustin Pedroia and Jacoby Ellsbury during Epstein's tenure as general manager of the Boston Red Sox.
"I've never put a guy on an Opening Day roster who hadn't played in the big leagues previously. In 13 years, I've never done it," Epstein told ESPN. "I'm not saying I'd never do it, but the general rule, the presumption, is to allow those guys to go out, play, get comfortable, get in rhythm, and come up when you handpick just the right moment for them to have success."
Bryant was named Minor League Player of the Year in 2014 after blasting 43 home runs in his first professional season. Prior to that, he was MVP of the Arizona Fall League. Bryant was the No. 2 overall pick out of the University of San Diego in the 2013 amateur draft. Bryant won the Golden Spikes Award as the nation's top college player in 2013.
If Bryant breaks camp with the Cubs, he can become a free agent after the 2020 season. The Cubs, however, can push that back to 2021 because of service time if Bryant stays in the minors until at least mid-April this season.
Epstein has never indicated money or control of the player is part of his decision-making process.
"I know you think it's about the business side of the game," Epstein said on the telecast. "We haven't even gotten there because we're focusing on the baseball part of the game and his development. We'll see what path he follows."
MLB commissioner Rob Manfred has said he supports whatever move the franchise elects to make.
"I think the Cubs -- I know the Cubs -- will make decisions that are best for the long-term competitiveness of that club," Manfred said.
Manfred also spoke out against Bryant's agent, Scott Boras, who is of the mind his client should be on Chicago's Opening Day roster.
"I don't think the Cubs' decision with respect to what's going to happen with Kris Bryant is really any of Mr. Boras' business," Manfred said.
A natural third baseman, Bryant played left field for the first time this spring on Thursday, recording an assist. He also struck out three times -- all looking -- against Angels starter Jered Weaver.
Information from The Associated Press was used in this report.