You can whine about run differential all you want but it is a good predictor of future performance... of course it is still not a guarantee of anything.
Like July 2015 when the Jays had a middling record despite having a huge run differential they made some moves this year at the deadline and eventually the season turned around. In both cases it turned around fairly quickly to get them back in the race.
It also helps down the stretch that they are starting to get some stability in their bullpen after a few acquisitions (Cimber, Richards) are paying off and some returns from injuries of strong arms (Pearson, Merryweather). That being said Pearson and Merryweather have had some up and downs in their first week back... if those two stabilize it will be very big for the team.