Hill joined the starting rotation of the Cubs after spring training, and was the #4 starter in the rotation behind Carlos Zambrano, Ted Lilly, and Jason Marquis. He pitched against the Milwaukee Brewers for his first start of the 2007 season, throwing a perfect game through the first five innings, and finishing with allowing just one hit, and one run over 7 innings pitched. He continued to excel during April, leading some to speculate that he was taking over as the ace in the Cubs rotation while he assembled a streak of 18 consecutive innings without an earned run.