Mailloux exited Saturday's preseason game after a fight with Chicago Blackhawks forward Cole Smith and did not return. He has since undergone surgery to address the injury and will likely miss at least eight weeks. It's an unfortunate blow for Mailloux, who began looking more comfortable toward the end of his rookie season in 2025-26 and was in line to take a step forward with the Blues in 2026-27.
Tucker played his first full NHL season in 2025-26, scoring 17 points (3G / 14A) in 69 games, and hopes his role will grow in 2026-27. That said, the 26-year-old defenseman suffered a lower-body injury that will sideline him, at least temporarily, for a portion of training camp.
Barron was drafted 25th overall by the Colorado Avalanche in the 2020 NHL Entry Draft. While he hasn't lived up to his first-round billing, Barron has become a serviceable bottom-pair defenseman in the NHL. The 24-year-old scored nine points (0G / 9A) in a career-high 52 games last season with the Nashville Predators.
Dube has not played an NHL game since the 2023-24 season, but could get a shot after signing a one-year contract with the St. Louis Blues. The 27-year-old scored 37 points (20G / 17A) last season in 46 games with the Springfield Thunderbirds (AHL).
Johnston has struggled to be a full-time NHLer over his career, but at age 31 in the 2025-26 season, he had a breakout season in a fourth-line role for the Anaheim Ducks, tallying 14 points (3G / 11A), 107 penalty minutes, and 192 hits in 62 games. He earns himself some security, joining the Blues on a three-year contract worth $6 million ($2M AAV).
Berggren was acquired mid-season in 2025-26 by the Blues off waivers from the Detroit Red Wings and made enough of an impact with his new team to earn a one-year contract extension. The 25-year-old Swedish forward, the 33rd-overall pick in the 2018 NHL Entry Draft, scored 16 points (6G / 10A) in 36 games with the Blues last season.
Carlo's short tenure in Toronto is over after a season and a half after the team announced Saturday that St. Louis had acquired the 29-year-old defensemen for the 73rd overall pick in 2026 and the 76th overall pick. Carlo not only failed to score in 2025-26, but only appeared in 55 games due to injury, ending the season with seven points, 37 PIMs and a +4 plus/minus.
After four full seasons in Anaheim, Mason McTavish has been acquired by St. Louis for the No.15 overall pick and the No.29 overall pick on Friday. The 23-year-old was Anaheim's 2021 1st round pick (3rd overall) and had 17 goals, 41 points and 42 PIMs in 75 games played in 2025-26. He is expected to be a key part of St. Louis' top-six for the 2026-27 season.
St. Louis has solidified its goaltending depth after it announced the Blues had signed Georgi Romanov to a two-year, two-way contract extension. The 26-year-old last appeared in the NHL with San Jose in 2024-25, going winless across eight appearances. He is expected to start the 2026-27 season in Springfield (AHL), where he shared the Thunderbirds crease last season, going 9-12-4 with a .896 SV% and 3.29 GAA.
