The Diamondbacks acquired the struggling left-hander from the Detroit Tigers on Tuesday for right-hander Billy Buckner, and they will insert the energetic and colorful pitcher into their starting rotation Saturday against the Rockies.
"Just very excited," Willis said. "Ironically, I just purchased a house in Arizona. I'm very excited, very eager to get out west and enjoy some of the good weather and play some good ball.
Once considered one of the top pitchers in baseball, Willis battled vicious control problems while with Detroit, for which he won just two games in three seasons after being traded by the Marlins after the 2007 season.
He has had decent results this season - a 4.98 ERA in nine games (eight starts) - but has struggled to throw strikes, walking 29 in 43 1/3 innings.
Willis burst onto the scene in 2003, posting a 3.30 ERA in 27 starts for Florida, capturing the NL Rookie of the Year award and helping the Marlins win the World Series. In five seasons with Florida, he averaged more than 200 innings with a 3.78 ERA.
