The St. Louis Blues are quite clearly no longer the team they were when they lifted the Stanley Cup back in 2019. Many of the team's stars from that year have left the club. And now the Blues are looking to build themselves back up without truly tearing it all down.

The Blues missed the Stanley Cup Playoffs in 2023 and picked within the top 15 of the 2023 NHL Draft. St. Louis did not go crazy in NHL Free Agency this summer. In fact, their biggest addition came through a trade with the Philadelphia Flyers.

The Blues acquired forward Kevin Hayes from Philadelphia for a late-round pick. Hayes was initially part of a larger trade involving Travis Sanheim and Torey Krug, but that fell apart thanks to Krug's no-trade clause.

Outside of that, St. Louis didn't do too much. They signed Mackenzie MacEachern, Oskar Sundqvist, and Alexi Torpchenko to provide some depth, and that's about it. As a result, roster spots remain open for the team's prospects to potentially take. Here are three of those prospects that St. Louis Blues fans should keep their eyes on.

3) Zach Dean

Dean is entering his first season in professional hockey. The 20-year-old scored 33 goals and 70 points in just 50 games for the Gatineau Olympiques in the Quebec Major Junior Hockey League. He added a further 10 goals and 26 points in 13 QMJHL Playoff games.

It's entirely likely that Dean begins in the AHL with the Springfield Thunderbirds. However, given the current roster setup, it isn't completely out of the realm of possibility that the 20-year-old makes the immediate leap to the NHL.

A strong performance in training camp could push someone like Jake Neighbours into the AHL. Perhaps one of the team's depth signings begins the year in the AHL, as well. It's up to Dean to play well and potentially force the Blues into changing their immediate plans.

2) Zachary Bolduc

Bolduce actually competed for a roster spot last fall and had a legitimate shot at making it. Unfortunately, however, he was taken out of the running rather early in training camp. He went back to the QMJHL where he absolutely dominated. The 20-year-old scored 50 goals and 110 points in 61 games for the QMJHL champion Quebec Remparts.

Bolduc does provide some versatility for the Blues. He was drafted as a center back in 2021. However, he has played primarily as a left winger for the Remparts. He could stick on the wing or move back to the middle for the Blues.

Bolduc, like Dean, faces an uphill battle for a roster spot. However, he is clearly for the next step given his performance this past season. He will have to steal someone's job to break camp in the NHL, but Bolduc might just be up for the task.

1) Scott Perunovich

Perunovich has long been considered one of St. Louis's top blueline prospects. He has struggled with injury since hearing his name called in the 2018 NHL Draft. To this point, he has played just 19 games for the Blues in his career.

This past season saw the 24-year-old suffer an unfortunate shoulder injury before the season. It cost him an opportunity to break camp with the NHL squad. However, he did play 20 games in the AHL, producing at a point-per-game pace.

If Perunovich wants to make the Blues roster, two things need to happen. First, he needs to remain healthy. Next, he needs to beat out some stiff competition. Established NHL options in Robert Bortuzzo and Marco Scandella stand in his way. He faces an uphill battle, but if he can show the talent that created the hype around him in the first place, it's a battle he can certainly win.