Colorado Rockies Top Prospect Carson Palmquist Expected to Make MLB Debut

Carson Palmquist was scratched from his Triple-A start on Thursday, setting the stage for the No. 9 prospect in the Colorado Rockies' farm system to take on the Arizona Diamondbacks on Friday.

Scottsdale, AZ, USA; Colorado Rockies pitcher Carson Palmquist (91) throws in the bullpen during Spring Training camp at Salt River Fields. | Rick Scuteri-Imagn Images

The Colorado Rockies are likely to turn to a fresh face for their series opener against the Arizona Diamondbacks on Friday.

Veteran Germán Márquez will start Saturday, while rookie Chase Dollander is penciled for Sunday. As for Friday, the Rockies have yet to announce a starting pitcher.

Carson Palmquist was slated to start for Triple-A Albuquerque on Thursday, but he was scratched at the last moment. MLB.com's Thomas Harding was the first to connect the dots and report that Palmquist was in line to start in the big leagues on Friday.

Palmquist, the No. 9 prospect and No. 1 left-handed pitcher in Colorado's farm system, is 2-2 with a 3.82 ERA, 1.132 WHIP and 11.5 strikeouts per nine innings through seven minor league starts this season. The 24-year-old southpaw will be making his MLB debut if he does indeed get the nod for the Rockies on Friday.

No announcement has been made, but signs point to the #Rockies    selecting LHP Carson Palmquist, their No. 9 @MLBPipeline prospect, to make his Major League debut in a start tomorrow night at Arizona.https://t.co/iaAWFfoldf

— Thomas Harding (@harding_at_mlb) May 15, 2025

Colorado picked Palmquist in the third round of the 2022 MLB Draft, following his time at Miami (Fla.). He proceeded to make 15 starts in High-A, 22 starts in Double-A and 16 starts in Triple-A as he rose through the ranks.

First pitch for Friday's series opener between the NL West foes is scheduled for 9:40 p.m. ET.

Colorado's rotation is lined up to feature a pair of highly-touted rookies in Palmquist and Dollander, plus three vets in Márquez, Antonio Senzatela and Kyle Freeland.

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