I specifically heard them refer to it at 7:30 AM on their newscast. The reporter said "you can hear the Leaf game here on 680, while for those looking for the news will find it on our live stream."
It was pretty definitive.
As noted, the problem may be that the Jays/L.A. game starts at 9:38 PM our time. Even with hockey facing off at 7 PM this time around, there's no way it will be over in time.
Could 590 be carrying the Leafs in a simulcast until the Jays start, telling listeners to tune down the dial? I would find that very surprising, but stranger things have happened.