Oakland made Isringhausen their closer. He posted a 2.13 ERA in his half-season with Oakland. His 96 mph fastball and knuckle-curve moved so much and broke so sharply that he sometimes had trouble keeping them out of the dirt. In his prime he was one of the games best closers and was elected to the All Star game twice, in 2000 with the Athletics and 2005 with the St. Louis Cardinals. With the St. Louis Cardinals, from 2002 to 2008, he pitched a minimum of 42 innings per season with a maximum era of 3.55, though he topped out in 2008 with a 5.70 ERA in 42.2 innings; he posted ERAs below 2.50 in each of his first two seasons with the club and led the National League with 47 saves in 2004.