Brown played in three straight games but will be replaced by Brandon Carlo (undisclosed) in the lineup on Saturday.
Regula was recalled from the AHL and will play in his first NHL game since March 10th. Regula will draw into the lineup to replace Calvin de Haan, who has a lower-body injury. Regula has no points in six NHL games so far this season.
Attard was a third-round pick in 2019 and recently signed his entry-level contract following his third year at Western Michigan University. He will replace Keith Yandle, who will be a healthy scratch, snapping his ironman streak.
Brown was acquired from the Senators at the trade deadline and is set to make his Bruins debut on Thursday. Brown, who had six assists, 106 hits and 57 blocked shots in 46 games with Ottawa, will replace Connor Clifton in the lineup.