...Quintana had 2 horrible starts back to back that have skewed his numbers (ERA went from 3.92 to 5.60), just like Tanaka...Quintana is still a solid pitcher and has been his whole career, one of the most consistent in Baseball....he's still striking batters out and at a higher rate than ever before and there's no drop in his velocity...he has however, uncharacteristically walked more batters and given up more HRs than usual...but IMO, he'll be fine and still worth acquiring if the price is right.
...not really fair to give Tanaka a pass, while at the same time condemning Quintana.