Hoffman was charged with an unearned run in the fourth when right fielder Mike Tauchman dropped an Andrew Toles fly ball. He walked Cody Bellinger with a base open and departed to allow reliever Scott Oberg to escape the jam.
"I felt great, a lot better than expected, going out on a dreary day in the rain and stuff like that," said Hoffman, the key acquisition from the Blue Jays in the 2015 trade that saw the Rockies give up star shortstop Troy Tulowitzki. "The main focus today was executing pitches. I think I executed darn near all of them today."
Hoffman, 24, ranked No. 44 on the MLB.com Top 100 Prospects list, showed improvement from last year, when he gave up a .306 batting average with runners on base while going 0-4 with a 4.88 ERA in eight games (six starts).
Hoffman induced a double-play in the third, then battled with a full count against Corey Seager before inducing a fly to center. His strikeouts of Franklin Gutierrez and Joc Pederson came after Yasmani Grandal's leadoff single in the fourth. The last hit off Hoffman, Yasiel Puig's jam-shot single, came when center fielder Noel Cuevas and second baseman Alexi Amarista miscommunicated.
Key for Hoffman was simplifying his delivery from the stretch. There's no high knee lift this year.
"Last year, one of the big downfalls I had when I came up was I was a little bit slower to the plate, just trying to keep my weight back and get on top of the ball a little bit," Hoffman said. "This offseason, we worked on making sure I was a little bit quicker and making sure my stuff wasn't going to suffer from being quick to the plate. It was a quick fix for me."
Added manager Bud Black: "[Hoffman] is working on a few things he needs to clean up, just to get his timing right."
• Outfielder David Dahl was scratched from the original lineup, in left field, because of minor back soreness. "We wanted to be really cautious -- overly cautious," Black said. "We think he's going to be fine. He's been feeling it for a couple of days."
• Oberg fired several effective sliders, then caught Charlie Culberson looking at a third strike with the bases loaded.
Thomas Harding has covered the Rockies since 2000, and for MLB.com since 2002. Follow him on Twitter @harding_at_mlb, listen to podcasts and like his Facebook page. This story was not subject to the approval of Major League Baseball or its clubs.