As this heat map shows, Mariano Rivera -- you may have heard of him -- has made a little adjustment in recent weeks. Since his mid-August funk, he's been throwing his cutter more on the low outside corner to left-handed hitters.
On the left: Rivera's pitch location through Aug. 11. On the right: His pitch location since. And it's been working as lefty hitters were batting .269 against him on the season through Aug. 11, but have gone 3-for-23 since, and he's allowed just one run in 14 innings.
(Thanks to Mark Simon for the graphic.)