The trade was made Saturday.
The 24-year-old McNeill has five goals, one assist and 36 penalty minutes in 18 games with the American Hockey League’s Texas Stars this season. He has played in 312 AHL games since the 2011-12 season.
McNeill has played in two NHL games — one with Chicago in 2015-16 and one with Dallas in 2016-17.
The 25-year-old O’Brien has three points and 27 penalty minutes in 21 games for the AHL’s Milwaukee Admirals this season. He has appeared in 188 career AHL regular-season games.