"You all have a chance to be a good ballplayer," he said to the attentive group.
He asked if the young players had heard of Joey Votto. A resounding 'yes'.
Justin Morneau? Another big 'yes'.
"They are no different than you guys are. They played in the same leagues as you do now," O'Halloran said of the two Canadian big leaguers, who are both former MVP winners.
O'Halloran, who played in one big league season with the Florida Marlins, is one of four former pros who led the first ever Canadian clinic hosted by the Major League Baseball Players Alumni Association. The MLBPAA brings the event to thousands of children in every corner of the United States each year.
"When I got the email from [MLBPAA], I was excited to do it because I know how much baseball has grown since I was a kid," the 45-year-old said as the players left the field. "There are a lot more Canadian players in the Major Leagues, and there are players who are a lot better that have a bigger impact in the Major Leagues."
The students of the game divided into four groups under O'Halloran, Toronto-natives turned Toronto Blue Jays, Rob and Rich Butler, and former Atlanta Braves pitcher Mike Remlinger. They learned the basics of proper throwing, infield duties, catching fly balls in the outfield and hitting balls out of the park.
"Baseball is a game that, unless you've been exposed to it ... until you get a chance to come out here, you might not know [what it's about]," O'Halloran said. "Maybe you like what you saw and you tell your mom and dad that you want to play, or you see your friends, it looks fun and you want to be as good as them."
Marcus Turino is 8 years old and he already knows he wants to play in the Major Leagues. He plays for a local team and he loved the opportunity to learn more (and get some extra autographs on his grey Blue Jays cap) from the guys who've been there and done that under the stadium lights.
His cousin, Ridge Leahmann, came along to the MLBPAA event. The 12-year-old went to his first Blue Jays game with Marcus on Saturday.
"The clinic was really fun," Leahmann said. "I learned how to catch better, how to hit better."
He is the perfect example of O'Halloran's mantra. Leahmann doesn't play in a league or know too much about the game, but two days of Toronto baseball leaves him smiling. Leahmann nods when asked if joining a team next summer is something he wants to do.
"I think this is great. [Marcus] watches a lot of baseball. He's in awe of what these guys do and represent," said his father, Paul Turino, after the event. "He's been looking forward to this for a long time. We really respect the message [here]."
O'Halloran is humble about his contributions to baseball outside of his time as a player. He coached the Canadian national team in 2009, a roster with deep talent including Morneau, Votto, Blue Jays third baseman Brett Lawrie and MLB All-Stars Jesse Crain and Russell Martin.
"I feel a responsibility to pass on the knowledge from the coaches before me ... some of those guys who really knew the game," O'Halloran said. "I don't care how good you are, but if you're willing to listen and you want to get better, I'm willing to pass it on to you."
The legacy that the Legends for Youth clinic brings in its first stop to Toronto is one that will continue to inspire the community around Dan Lang Field.
Scott McRoberts, director of athletics and recreation at the Scarborough campus, is excited to have baseball added to the repertoire of offerings for eight priority neighborhoods that use the University of Toronto facilities. More than 120 participants were involved in the free tennis program offered next to the ball field this summer for just the second year.
There's an overwhelming positivity on the field that carries into the conversations between the kids and their parents. When the bats and gloves are packed, it's clear that there are a lot of enthusiastic ambassadors for the game of baseball.
That's the message that MLBPAA will keep bringing when they grow the program to reach even further across the globe next year through the diverse talent pool of alumni in different countries.
"We, as former players, should come out and show everybody that we're average guys," O'Halloran said. "The Butlers and myself grew up around here, played in the same organizations that they play in, and look what happened to us."