I am accepting that he has been very good. He looks like a different pitcher this year, one who has the stuff to start. He's been used as a backend reliever in low-leverage situations. (1, 2) Lately that has changed a bit but, the Jays still have 3 or 4 options ahead of him including 2 LHP (not to mention Dustin McGowan a week or so away, Santos coming back at some point and Luis Perez coming back at the AS break).
With Esmil Rogers getting spot starts the Jays should use this opportunity to piggyback Cecil and begin stretching him out. Start with 3IP and give him a month (4-6 outings) or so to get used to it and then bump him to 5IP. If he has efficient outings let him get to 6IP at the tail end of the year, if not use that BP depth and pull him after 5IP.
1. http://www.fangraphs.com/leaders.aspx?pos=all&stats=rel&lg=all&qual=10&type=c,63,64,65,68,70,13,122,6&season=2013&month=0&season1=2013&ind=0&team=14&rost=0&age=0&filter=&players=0&sort=6,d,
2. http://www.fangraphs.com/statsplits.aspx?playerid=2660&position=P&season=2013#standard