While the teams squared off before a sellout crowd at Knology Park, the right-hander was toiling five miles away against a collection of Minor Leaguers.
Halladay was scheduled to pitch Friday against the Reds in Sarasota, Fla., but the game was rained out. Manager John Gibbons decided not to let the Tigers catch a sneak preview of his ace, who is slated to start the season opener on April 2 in Detroit.
That was just fine with Tigers manager Jim Leyland.
"It doesn't matter," Leyland said. "We know about him, and I don't like [to] see him anytime."
Halladay allowed three hits in five scoreless innings Saturday against the Triple-A affiliate of the Phillies. He notched seven strikeouts and walked none.
Halladay achieved all that success without benefit of his cut fastball.
"I'm going to wait one more start. Probably next time out, I'll throw it a little," he said. "I'm just working on location -- that's obviously the most important thing."
Chacin update: Left-hander Gustavo Chacin originally was penciled in to face Detroit on Saturday, but he is projected to follow Halladay and right-hander A.J. Burnett to the Comerica Park mound in the opening series.
The Blue Jays have greater concerns with Chacin than keeping him hidden from the Tigers. The 26-year-old Venezuelan was arrested early Friday morning for driving under the influence of alcohol in nearby Tampa.
Chacin was stopped by police at 3:43 a.m. ET and booked on a misdemeanor charge. Police reports indicate his blood alcohol level measured .150, substantially higher than the legal limit of .08. He was released on a $500 bond.
"It's a serious mistake. We all make mistakes," Gibbons said. "He'll learn from it. We'll all learn from it."
Regarding whether the club will take any disciplinary measures outside the legal system, Gibbons wouldn't say.
"That's between us, but the justice system gets your attention pretty good these days," he said. "And they should."
"The guy made a mistake. What are you going to do?" he said. "You try to work with him, not against him."
Chacin pitched five innings against a Double-A affiliate of the Phils, allowing two earned runs on five hits. He met with reporters upon his return to the clubhouse, but didn't discuss his legal troubles.
"Sorry. I apologize for that," he said. "No comments right now -- just baseball."
More Minor details: Setup candidate Brandon League pitched one perfect inning against Minor Leaguers, striking out two of the three batters he faced. The right-hander, who has been rehabilitating a strained lat muscle in his pitching arm, was delighted with the live test.
"It felt good to have someone up there who's swinging the bat, trying to get a hit off you," he said. "I had some adrenaline pumping, so that was good, just to get a game-like feeling."
League is convinced it's time to rejoin his teammates.
"I'm ready for one of these games now," he said.
Another shot: Third baseman Troy Glaus, who was expected to miss a few games after receiving a cortisone shot in his left shoulder Thursday, returned to the starting lineup. He went 0-for-2 at the plate and committed a throwing error.
Quick hits: The Blue Jays wore green jerseys and both clubs donned green caps in observance of St. Patrick's Day. The jerseys were autographed and distributed to fans through a charitable raffle. ... Major League Baseball Players Association executive director and general counsel Donald Fehr discussed union matters with Blue Jays players in a lengthy morning meeting.
Roster moves: Following Friday's rainout, Toronto optioned right-hander Ty Taubenheim, infielder John Hattig and outfielder Adam Lind to Triple-A Syracuse. Infielder Rob Cosby was reassigned to Minor League camp.
Before Saturday's game, infielder Russ Adams also was optioned to Syracuse.
Up next: Burnett will oppose Houston right-hander Roy Oswalt at 1:05 p.m. ET when the Blue Jays visit the Astros on Sunday in Kissimmee, Fla.
Bob Bellone is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.