Adam Stern (London, ON), George Kottaras (Markham, ON) and John Axford (Simcoe, ON) all appeared in the same game for the Milwaukee Brewers on Thursday, May 20th.
22 times there has been 3 Canadians on the same team in the same year since 1884.
Cincinnati Reds 1884 – John Irwin, Jim McKeever, Patrick Scanlan
Pittsburgh Pirates 1884 – Jimmy Knowles, Billy Reid, Frank Smith
Washington Nationals 1884 – John Humphries, Henry Mullins, Alex Gardner
Cleveland Blues 1885 – Ed Nolan, Pop Smith, Bill Phillips
NY Metropolitians 1887 – Jimmy Knowles, Jon Morrison, Fred O’Neill
Chicago Cubs 1903 – Clearence Currie, Alex Hardy, Larry McLean
Boston Braves 1912 – Frank O’Rourke, Bill Jones, Doc Miller
Pittsburgh Pirates 1946 – Ed Bahr, Frank Colman, Lefty Wilkie
Milwaukee Braves 1961- Claude Raymond, Ron Piche, Ken MacKenzie
Houston Astros 1965 – Claude Raymond, Ron Taylor, Ken MacKenzie
Toronto Blue Jays 1991 – Denis Boucher, Vince Horsman, Rob Ducey
Boston Red Sox 1992 – Paul Quantrill, Peter Hoy, Mike Gardiner
Montreal Expos 1993 – Denis Boucher, Larry Walker, Joe Siddall, Matt Stairs, Mike Gardiner
Toronto Blue Jays 1997- Rob Butler, Paul Quantrill, Paul Spoljaric
Seattle Mariners 1998 – Rob Ducey, Paul Spoljaric, Ryan Radmanovich
Minnesota Twins 2004 – Jesse Crain, Justin Morneau, Corey Koskie
Atlanta Braves 2006 – Peter Orr, Chris Reitsma, Scott Thorman
KC Royals 2006 – Ryan Braun, Matt Stairs, Aaron Guiel, Mark Teahen
Baltimore Orioles 2007 – Adam Stern, Adam Loewen, Erik Bedard
Milwaukee Braves 2010 – Adam Stern, George Kottaras, John Axford
Montreal Expos 1993 actually had 5
KC Royals in 2006 actually had 4
However, only 9 of these teams had three Canadians play in the same game as far as I can tell. There are only daily game stats back till 1946 so for the years 1912, 1903, 1887, 1885, 1884 we can’t be sure.
Pittsburgh 1946 – Ed Bahr, Frank Colman, Lefty Wilkie- June 2
Houston 1965 – Claude Raymond, Ron Taylor, Ken MacKenzie – July 23
Montreal 1993 – Denis Boucher, Larry Walker, Joe Siddall – Sept 6, 18, Oct 3
Toronto 1997 – Rob Butler, Paul Quantrill, Paul Spoljaric – April 20, June 1, 11, 13, 28, July 2,3,5
Seattle 1998 – Rob Ducey, Paul Spoljaric, Ryan Radmanovich – May 12, Sept 19
Minnesota 2004 – Jesse Crain, Justin Morneau, Corey Koskie – Aug 5,7,8,21,26,27, Sept 24,29, Oct 1
Atlanta 2006 – Peter Orr, Chris Reitsma, Scott Thorman – July 1
KC Royals 2006 – Ryan Braun, Matt Stairs, Aaron Guiel – Sept 19, 22, 24, Oct 1
Milwaukee 2010 – Adam Stern, George Kottaras, John Axford – May 20
So 29 times 3 Canadians have played in the same game!