Randy Johnson would have to be the best blueprint for Sale, given his delivery and his slider. Johnson had some injury problems when he was younger. I figured if Sale was going to get a big injury, it would have been last year, but it didn't happen.
A knuckle curve is more fitting for someone with a much higher delivery than Sale, and over the top. Verlander stopped using it thanks to blistering. I would be cool with Hector or Nate learning one though.