Mark Leiter Jr. has ridden his reverse splits to a steady job in the Cubs’ bullpen, and he’s liable to keep it for a while, since he’s effective and cheap. He’s been good for 0.6 WAR in 22u2154 innings, with 33 strikeouts and seven bases on balls, and is currently riding a .926 WHIP.
He throws a fastball and a splitter. His splitter is a weapon. He gets most of his strikeouts with it. It’s a difference-maker. He also has a sinker, cutter, and a curve, but doesn’t use them often, especially against lefthanders.