Obviously, it's going to be different with each player, but Dempster made the transition to starter after pitching less than 100 innings for 3 straight seasons. 2005 - 92.0 2006 - 75.0 2007 - 66.2 He has since posted 4 straight with 200+ innings.
Watching this video, I can't help but feel bad for the guy. http://www.wgntv.com/videobeta/8826fadb-99e7-41ce-8c8f-a097e14d94c8/News/Unedited-Video-Jim-Hendry-out-as-Cubs-GM-press-conferenc