He has four goals and four assists in 12 games this season with the Eagles and has played in 17 career NHL contests with the Washington Capitals. O'Brien will start tonight's contest on a line with Pierre-Edouard Bellemare and J.T. Compher.
The Halifax, Nova Scotia, native is taking the spot previously held by Logan O'Connor, who will be out "weeks," according to head coach Jared Bednar after morning skate. O'Connor did not play in the final two periods on Wednesday against the Arizona Coyotes due to an upper-body injury.
Goaltender Jonas Johansson will make his second career start for the Avalanche, with Philipp Grubauer being the backup. Johansson made his team debut on March 23 where he made 28 saves in a 5-4 shootout loss at the Arizona Coyotes.
Grubauer did not take part in morning skate, as Bednar said he wanted to give the keeper the practice off to get him some more rest. Grubauer had started four straight games and is 10-0-1 in his last 11 appearances, being named the NHL West Division Player of the Month for March on Thursday.
Bednar said he isn't making any other changes to his lineup for the first half of the consecutive-night set versus St. Louis. It is the first meeting between the teams since the Avs won 8-0 in the second game of the season on January 15.
Below is the Avalanche's projected lineup for tonight's game against the Blues. All forward combinations and defensive pairings are subject to change.
Forwards
92 Gabriel Landeskog - 29 Nathan MacKinnon - 96 Mikko Rantanen
20 Brandon Saad - 91 Nazem Kadri - 95 Andre Burakovsky
13 Valeri Nichushkin - 17 Tyson Jost - 72 Joonas Donskoi
37 J.T. Compher - 41 Pierre-Edouard Bellemare - 38 Liam O'Brien
Defensemen
49 Samuel Girard - 7 Devon Toews
27 Ryan Graves - 8 Cale Makar
2 Dan Renouf - 34 Jacob MacDonald
Goaltenders
35 Jonas Johansson (starter)
31 Philipp Grubauer (backup)
Taxi Squad: Sheldon Dries, Keaton Middleton, T.J. Tynan, Adam Werner
Injury Report: Bowen Byram (upper body), Matt Calvert (upper body), Pavel Francouz (lower body), Erik Johnson (upper body), Logan O'Connor (lower body)