Dahl has been sidelined since late February with a rib injury, and the Rockies have not released a timetable for when he will return.
"I'm disappointed, for sure," Dahl told the Post on Sunday. "It would have been my first Opening Day, but it is what it is. I have to get fully healthy now so I can help the team later."
Dahl was scratched from the Rockies' lineup on Feb. 27 with what the team initially described as back soreness. He was diagnosed with a stress reaction in his rib a week later, but Rockies manager Bud Black said at the time that the team hoped Dahl would miss only a few weeks.
The Rockies begin their season on April 3 with a four-game series in Milwaukee before their home opener on April 7 against the Dodgers.
Dahl, 23, has been doing light drills and cardio work in recent days and is scheduled to undergo follow-up tests on his rib Friday.
"It's tough to sit, for sure," Dahl told the Post. "But I suppose it's better for it to happen now instead of at midseason. The good thing is, it doesn't hurt now."
The Rockies have been plagued by injuries throughout spring training. Starting first baseman Ian Desmond (hand) and catcher Tom Murphy (forearm) both will be sidelined for the first few weeks of the regular season, and starting pitcher Chad Bettis stepped away from baseball earlier this month to undergo chemotherapy after discovering that his testicular cancer had spread.
Dahl was selected with the 10th overall pick in the 2012 draft and enjoyed a solid start to his major league career last season, batting .315 with seven home runs in his first 63 games with the Rockies.
The Rockies expected Dahl to open the season as their starting left fielder but likely will turn to Gerardo Parra during his absence.
Information from The Associated Press was used in this report.