The St. Louis Blues have taken the better part of the past four seasons rebuilding the defensemen portion of their prospect pipeline. While there is still room to continue building, the pipeline at this point is more "deep" than it is considered to be filled with "star-studded". With Theo Lindstein set to become more of an NHL regular this coming season, the pipeline takes a little bit of a shuffle.
Here is a look at the Blues' top-five prospect defensemen ahead of the 2026-27 season.
Adam Jiricek
The 20-year-old right-shot defenseman was selected 16th overall in the 2024 NHL Entry Draft and is finally staying healthy and looking like the player scouts hoped he would. During the 2025-26 season, Jiricek put up 19 goals and 59 points in 55 games with the Brantford Bulldogs, won the Best Defenseman award at the World Juniors, and even got a taste of the AHL with the Springfield Thunderbirds during the Calder Cup run. He has the range, heavy shot, and skating, he continues to improve upon, and the stamina to play long minutes for his team.
Expectation: Jiricek has the talent to safely become a top-four, two-way defenseman, even a top-pairing defenseman down the line, should the development continue to rise. He should be starting heavy minutes for Springfield for the 2026-27 season and could even get a sniff in the NHL in the latter portion of the season.
Lukas Fischer
The soon-to-be 20-year-old, 2024 second-round defender has officially concluded his OHL career after a mid-season trade from Sarnia to Sault Ste. Marie. Between the two teams, he notched 44 points (8-36--44) in 65 regular season games. He uses his 6-foot-3-inch reach, stride, and two-way play. He will need to scale the penalty minutes down a notch or two, but he continues to grow into a physical workhorse.
Expectation: Fischer has the potential to become a strong, two-way left-shot defender and should develop into a regular on the second-pairing unit if his offense can continue to develop. A number four or five defenseman with second power play duties.
Colin Ralph
Taken 48th overall in 2024, the 20-year-old left Michigan State after two seasons in the NCAA and has signed his entry-level deal. Offensive production will never be Ralph's calling card, but the type of defender who plays a strong defensive, penalty-killing game. The 6-foot-4 blueliner is already weighing in at 229 pounds and will continue to develop as a bruising player to play against.
Expectation: Develop as a third-pairing defensive defenseman. He will push for a spot in Springfield as a regular defender for the 2026-27 season and a trusted penalty-killer in the near future.
Arseni Koromyslov
The 22-year-old left-shot defenseman has officially made his way from the KHL to North America ahead of the coming season. After averaging 17 minutes per game with Traktor, he will look to use his 6-foot-5 frame and range to his advantage with the Thunderbirds. Like Ralph, offensive production will not be his calling card, but he will use his defensive strengths to wreck players on the smaller North American ice.
Expectation: A future third-pairing defender or top-pairing AHLer if his game transfers appropriately from Russia. He projects more as an organizational depth piece instead of a lock for the top-four, though.
Michael Buchinger
The left-shot defender was once a point-per-game player in the OHL and a fantastic puck-mover after going 88th overall in the 2022 NHL Entry Draft. However, two seasons so far in the AHL and the offense has yet to follow with 20 points (8-12--20) in 109 games to this point. While his defensive game continues to grow, the offense will need to begin to take the next step to help push him into the conversation for an NHL promotion.
Expectation: An AHL top-four defender. If his development truly takes off, he could work his way into the conversation for a seventh defenseman.
Honoroable mention: William McIsaac
Drafted in the 5th round, 14th overall in the 2024 NHL Entry Draft, McIsaac has moved on from the WHL as Spokane's team captain, scoring 22 goals and 109 points in 270 regular season games, officially heading to the NCAA with UConn. The 6-foot-3, 205-pound right-shot defender has the defensive habits to push his game to the next level, and the NCAA should continue to do more to prepare him for the pro game.
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