June 2. He still posted decent numbers for the year and went 12–12 with a 3.87 ERA, including 11–6 with a 3.39 ERA from June to September. His 12 wins were tied for the most on the Marlins. Willis also led the Marlins in complete games (4), innings pitched (), walks (83), and hit by pitch (19). On June 20, Willis earned his 50th career win in a start against the Baltimore Orioles. On July 7, Willis hit a grand slam off of Mets pitcher José Lima, becoming the first pitcher to hit a grand slam since Robert Person did it in 2002. It was his fourth career home run. On September 20, 2006, he hit two home runs, off of Óliver Pérez and Roberto Hernández. He became the first pitcher since Randy Wolf in 2004 to hit two home runs in a game. 2007 season On January 15, 2007, Willis signed a one-year contract with the Marlins for $6.45 million, avoiding salary arbitration. In the 2007 season, Willis went 10–15 with a 5.17 ERA and a 1.60 walks plus hits per innings pitched. Up to that point, it was his worst season of his career. Willis led the National League in earned runs allowed with 118. During his career with the Marlins, Willis went 68–54 with a 3.78 ERA. He won at least 10 games each season during all five of his years with the Marlins from 2003 to 2007. Detroit Tigers On December 5, 2007, the Marlins traded Willis along with fellow All-Star Miguel Cabrera to the Detroit Tigers for Andrew Miller, Cameron Maybin, Mike Rabelo, Eulogio de la Cruz, Dallas Trahern, and Burke Badenhop. Willis signed a three-year, $29 million contract extension two weeks later. In his debut with the Tigers, Willis pitched five innings, gave up one hit, and three earned runs against the Chicago White Sox. In his next start, also against the White Sox, Willis injured his left knee and departed the game before even recording an out. Placed on the disabled list the next day, Willis had walked nine batters while striking out none in his first two outings. Command of his pitches became a trouble spot, and later in the season, Tiger manager Jim Leyland pitched him in relief for the first time, with little success. He was placed back into the rotation on June 3, 2008, to start in a loss