Toronto and Detroit are both currently ranked among the bottom 5 teams in baseball in relievers' ERA. Going back over the last ten years, the only teams that finished the season in the bottom 5 and made the playoffs were the 2005 Red Sox and the 2011 Rangers.
The '05 Red Sox were #1 in run scored and won the wild card before being swept in the 1st round by the White Sox. The 2011 Rangers came within 1 pitch of winning the World Series, but that seems like an aberration. They also finished 7th in starters' ERA and 3rd in runs scored.
The Blue Jays and Tigers both play in (as of right now) mediocre divisions and have the ability to score plenty of runs (ranked 2nd and 3rd in OPS). They have the 10th and 11th best ERA in their starting rotation, and Detroit (at least in theory) should have one of the best starting rotations in baseball. Being ranked near the bottom in relievers' ERA isn't something that can't be overcome, but it is a major hurdle.
The Tigers are always a threat to catch fire because of their starting pitching, but that usually doesn't last more than a series. The Blue Jays probably can't count on being able to outscore everyone in October. Absent significant improvement, however, I have a hard time seeing the Blue Jays or Tigers winning the World Series with their current bullpens.