Nah, the worst time to get cold would be in the upcoming week or two. Despite this slump the Jays have more than enough time to get back on track and win the division.
We have 3 lefties in the pen regardless. I don't see a problem with bringing the best one into a high leverage spot and hoping it's the most important lefty situation of the game.
Had to get Sanchez out of there and it was a high leverage situation against a lefty. I don't see anything wrong with going to our best LHP in that spot.