I think Sanchez/Estrada in the rotation with Norris in AAA is a good idea. However, if they decide to go with Sanchez and Norris, then there are ways to manage their innings using Estrada as the spot starter. For example, if one of the two is struggling in June, have Estrada take their spot in the rotation for 1-3 turns, and then put them back in the rotation after that, and so on. That way they periodically get a breather, and can still finish the season with an IP total around 170 or so (which I'm guessing is where they want to go after 130 IP in 2014 for both).