Lawrie suffered the injury while fielding ground balls prior to Wednesday night's game against the Angels. The ball took a bad bounce on the Rogers Centre Astroturf and hit Lawrie's bare hand.
The native of Langley, British Columbia, went for X-rays, which revealed the non-displaced fracture and resulted in him being placed on the 15-day disabled list.
"I was turning double plays, my top hand was down just to kind of guide the ball in, and the ball kind of took a funny hop at the last second," Lawrie said. "It kind of jumped in, when my hand was fully stiff, and it kind of just jammed my middle finger."
Blue Jays manager John Farrell estimated that the recovery time will be approximately four-to-six weeks. It's not expected to cause any delay to Lawrie's offseason schedule, as players typically use a similar time frame to recuperate from the long season.
It's the second time this year Lawrie suffered a broken bone in one of his hands. In early June, while still playing for Triple-A Las Vegas, Lawrie suffered a fractured left hand when he was hit by a pitch.
The pain and swelling isn't nearly as bad this time around, and the X-ray results caught him by surprise.
"I didn't think anything of it, and then we put it under the X-ray machine and sure enough there was something in there," Lawrie said. "I didn't really think there was going to be, just because I had hurt my hand a little while ago when I hit it on the roof of the dugout, and it kind of felt the same. But I guess, obviously not."
The 21-year-old Lawrie was originally listed in Toronto's lineup for Wednesday night. The late scratch caused Edwin Encarnacion to move from designated hitter to third base while David Cooper was inserted into the lineup at DH.
Lawrie finished his rookie campaign with a .293 average, nine home runs and 25 RBIs in 43 games.