He's implying the possibility that Pena falls to the same fate of Patterson, meaning there will be several threads a week here at the Cafe such as "When the heck will WMP stop K'ing?!?!" and "Drop Willy Mo for... ?"
Sure, he's trying to work out a kink in his style to K less, but that doesn't mean he's going to. That's all that's being said here.
Willy Mo's got a ton of that 'upside' thing people like to talk about, and if you have a strong team and can afford to take that risk, then by all means, take it, with the possibility of your team being even stronger. Same can be said about a cellar team willing to try new things. But, I wouldn't be comfortable relying on Pena for much, until he shows me a bit more.