 In 2008, Marcum got off to a good start, going 5–4 with a 2.65 ERA and 86 strikeouts in 98 innings, but an injury, followed by a handful of weak starts sent him to Triple-A on August 23.In September he was back in the starting rotation and he seemed to have returned to form.However, on September 19, days after an abbreviated start in which he left with elbow pain, the Jays released the information that Marcum would need Tommy John surgery and would miss the rest of the 2008 season and likely all of 2009.