He had a career-high 42 saves in , and enjoyed his best season in with a 4-1 record, 40 saves, 68 strikeouts, and a 1.92 ERA.
A four-time All-Star, Percival compiled a 29-38 record with a 2.99 ERA in 586.2 innings for the Angels. His 316 saves put him at 12th on the all-time list in Major League Baseball. However, his strikeouts per nine innings have gone down considerably from when he was an elite closer. In , his K/9 rate was 11.08. In 2002, 10.86. In , 8.76. And in 2004, it dropped all the way to 5.98. His fastball, once clocked consistently at 96 -100 MPH, was down to about 92 - 93 MPH in 2004, due to a degenerative hip condition that first appeared in 2003, which forced him to alter his pitching delivery.
Percival's contract with the Angels expired in 2004 and he became a free agent at the end of that season. Rather than bring Percival back, the Angels decided to turn to young phenom Francisco Rodríguez to close, motivated largely by Rodriguez's much lower price tag and concerns about Percival's age and health. The Angels offered to negotiate a reduced role (at a correspondingly reduced salary) for Percival to return as a setup man, but Percival decided to seek opportunities elsewhere that would allow him to remain a closer.
After attempting to recuperate, Percival reported to spring training for the Tigers in . However, on his first outing he again suffered significant pain and left the team. After spending the entire 2006 season on the Tigers' disabled list and working for the team as an advance scout, Percival's contract with the Tigers expired at the end of the 2006 season.
Though the he didn't pitch a game during the Tigers' run to the American League Championship, the team voted Percival a ring and a full playoff share. Appreciative of this gesture, he used the money to buy a suite at Comerica Park for the Tigers' wives.
Percival made his first appearance in the Majors since 2005 on June 29, 2007, against the Cincinnati Reds. He struck out the first batter he faced, David Ross, and was also credited with the win.
On November 29, 2007, he signed a two-year, $8 million contract with the Tampa Bay Rays. The contract contained up to $4 million in performance-based incentives. Rays manager Joe Maddon has said that Percival will be the closer in .