Blues coach Ken Hitchcock said he'd provide an update on Allen's condition at a later date.
"If Jake ever got hurt, there's a lot of confidence here in Carter right now," Hitchcock told the Blues website. "If Jake goes down, we've got no issue playing Carter at all."
Dennis Rasmussen scored 3:05 into the second period for the Blackhawks. Corey Crawford made 19 saves.
It was the preseason finale for the Blackhawks and Blues; they'll open the regular season at United Center on Wednesday.
Video: CHI@STL: Allen shaken up in the 1st, remains in game
Anthony Mantha helps Red Wings defeat Maple Leafs
Anthony Mantha broke a tie with 9:03 remaining in the Detroit Red Wings' 4-3 win against the Toronto Maple Leafs in the preseason finale for both teams at Joe Louis Arena.
Gustav Nyquist had a goal and an assist for the Red Wings. Dylan Larkin and Brendan Smith scored and Petr Mrazek made 28 saves. Thomas Vanek had two assists.
Auston Matthews, the No. 1 pick at the 2016 NHL Draft, had two assists for the Maple Leafs. Zach Hyman, William Nylander and Brooks Laich each scored a goal and Frederik Andersen made 19 saves.
Red Wings captain Henrik Zetterberg played for the first time this preseason; he sustained a knee injury during off-ice training and missed the World Cup of Hockey 2016 and most of training camp. Zetterberg had one assist in 18:36 of ice time.
The Maple Leafs open the regular season at the Ottawa Senators on Wednesday. Detroit plays at the Tampa Bay Lightning on Thursday.
Video: TOR@DET: Mantha fakes, scores through screen
Avalanche defeat Kings in Las Vegas
Gabriel Landeskog scored 37 seconds into overtime and the Colorado Avalanche rallied for a 2-1 win against the Los Angeles Kings at T-Mobile Arena in Las Vegas.
Jeff Carter gave the Kings a 1-0 lead in the second period before Avalanche forward Mikhail Grigorenko tied it late in the third to send the game to overtime.
It was the second preseason game held in Las Vegas in as many nights; the Dallas Stars defeated the Kings 6-3 in the first NHL game at T-Mobile Arena on Friday.
T-Mobile Arena will be the home of Las Vegas when it begins play next season.
Video: COL@LAK: Landeskog shows off hands on overtime winner
Steven Stamkos gets three assists in Lightning win
Center Steven Stamkos had three assists in his preseason debut for the Tampa Bay Lightning in a 5-3 win against the Nashville Predators at Amalie Arena.
Defensemen Victor Hedman and Anton Stralman also made their preseason debuts in the final exhibition game before the Lightning open the season Thursday against the Detroit Red Wings at home (7:30 p.m. ET; SUN, FS-D).
Forward Jonathan Drouin had a goal and two assists, and Ondrej Palat, Brayden Point and Nikita Nesterov each had a goal and an assist for Tampa Bay.
Goalie Ben Biship allowed two goals on 16 shots over two periods. Andrei Vasilevskiy played the third and made seven saves.
Forward Craig Smith scored two goals and goalie Pekka Rinne allowed five goals on 36 shots for Nashville, which plays its season opener Friday against the Chicago Blackhawks at Bridgestone Arena (8 p.m. ET; NBCSN, TVA Sports, CSN-CH).
Panthers defeat Devils at West Point Academy
The Florida Panthers scored four unanswered goals to defeat the New Jersey Devils 4-2 in their preseason finale at Tate Rink in West Point, New York.
It was the first NHL game played at West Point Military Academy.
Colton Sceviour, Aaron Ekblad and Vincent Trocheck each scored in the second period to give the Panthers a 4-1 lead.
Panthers forward Jaromir Jagr tied it 1-1 on the power play at 9:45 of the first period off a pass from Jonathan Marchessault.
Defenseman Andy Greene gave the Devils a 1-0 lead at 3:05 of the first on a pass from right wing Kyle Palmieri. Mike Cammalleri also scored and defenseman Yohann Auvitu got his sixth assist of the preseason for New Jersey.
Panthers forward Jonathan Huberdeau left the game in the first period and did not return.
The Panthers open the regular season Thursday against the Devils at BB&T Center (7:30 p.m. ET; FS-F, MSG+).
Video: Marchessault, Panthers beat Devils, 4-2
Ryan Spooner gives Bruins win in preseason finale
Forward Ryan Spooner scored with 3:12 left in overtime to give the Boston Bruins a 1-0 win against the Philadelphia Flyers in their preseason finale at TD Garden.
Spooner beat goalie Steve Mason with a wrist shot on a breakaway off a pass from forward David Backes.
Bruins goalie Tuukka Rask made 27 saves for the shutout. Mason made 22 saves.
Boston finishes the preseason 4-2-1. The Bruins open the regular season against the Columbus Blue Jackets at Nationwide Arena on Thursday (7 p.m. ET; FS-O, NESN)
Philadelphia finishes the preseason 4-2-2. The Flyers play their season opener Friday against the Los Angeles Kings at Staples Center (10:30 p.m. ET; FS-W, CSN-PH).
Video: Spooner's OT goal leads Bruins past Flyers, 1-0
Markus Granlund's late goal gets Canucks past Oilers
Markus Granlund broke a tie with 2:34 remaining in the Vancouver Canucks' 3-2 win against the Edmonton Oilers at Rogers Place.
Brandon Sutter and Sven Baertschi also scored for the Canucks, who will open the regular season at home against the Calgary Flames next Saturday. Jacob Markstrom made 34 saves.
Benoit Pouliot and Connor McDavid had goals for the Oilers. Cam Talbot stopped 18 of 21 shots.
Edmonton opens the regular season at home against the Flames on Wednesday.
Video: VAN@EDM: Granlund reaches out for nice deflection
Big third period sends Wild past Jets
The Minnesota Wild scored four third-period goals in a 5-1 win against the Winnipeg Jets.
Mike Reilly, Cristoph Bertschy, Marco Scandella and Charlie Coyle scored in the third to break a 1-1 tie. Zach Parise scored in the first period, and Devan Dubnyk made 17 saves.
Joel Armia scored for Winnipeg, and Michael Hutchinson allowed five goals on 34 shots.
Minnesota opens the regular season Oct. 13 at the St. Louis Blues (8 p.m. ET; FS-MW, FS-M, FS-WI).
Winnipeg hosts the Carolina Hurricanes, also on Oct. 13 (8 p.m. ET; TSN3, FS-CR).
Video: WPG@MIN: Reilly's shot goes through screen for PPG
Oliver Bjorkstrand scores twice in win
Forward Oliver Bjorkstrand had two first-period goals when the Columbus Blue Jackets defeated the Pittsburgh Penguins 5-3 at PPG Paints Arena.
Bjorkstrand scored a power-play goal at 8:54 of the first period and at even strength at 14:45 to give Columbus a 2-0 lead.
Brandon Saad, Boone Jenner and Matt Calvert also scored for Columbus.
Scott Wilson had a goal and two assists for the Penguins, who also got goals from Kris Letang and Evgeni Malkin.
Sergei Bobrovsky made 21 saves for the Blue Jackets. Marc-Andre Fleury made 26 saves for the Penguins.
Penguins captain Sidney Crosby did not play because of an illness, coach Mike Sullivan said after the game.
It was the final preseason game for each team.
Video: Bjorsktrand nets two in Blue Jackets' 5-3 win