I like the idea of this thread but I think the numbers are skewed a bit by how s***** the rotations have been in the past. Presumably Estrada, Sanchez and Norris will be able to fill in the rotation as long as needed, barring injury. In the past you had some really crappy pitchers getting starts and were removed for another piece of crap because, even as depth, they just weren't cutting it.
Guys who have made starts since 2010 include: Ramon Ortiz, Zach Stewart, Brad Mills, Luis Perez, Chien-Ming Wang, Bruce Tallet, Dana Eveland, Joel Carreno, Jesse Chavez (he sucked then), Shawn Hill, Aaron Laffey, Kyle Drabek, Jo-Jo Reyes, Marc Rzepczynski, Esmil Rogers, Jesse Litsch.
Those names have made 162 starts over the last five years. Every fifth day since 2010 somebody from the above melting pot of hot garbage has pitched for the Blue Jays.
And this doesn't even consider the bad years of Ricky Romero, Josh Johnson's disastrous year, McGowan in the rotation, Henderson Alvarez's bad year, Cecil's bad years in the rotation and others.
Their rotation seems to be better this year. I don't think 12 starts will have to come from outside the 8 guys you mentioned. And if they do and I'm sure they could do worse than Roberto Osuna, Miguel Castro and maybe even Jeff Hoffman late in the year.