Feldman is one of those guys who just gives up too many hard hit balls, he is basically a Dave Bush type. Wrigley is not a good fit for him. If the Padres signed him he could be a solid #3 for them, on the Cubs he is just a guy. Given the market this deal isn't bad at all, he likely will match Guthrie and it is only one year but this isn't going to do all that much for this particular Cubs roster. ERA is a team stat and it is heavily luck influenced. A pitcher can pitch exactly the same two years in a row and see his ERA jump over a full run per 9 on a regular basis. ERA is more or less worthless for evaluating a single season of a pitcher. FIP and xFIP try to neutralize this though they don't do a very good job of it. When you have multiple seasons of data you want to use all 3 stats and also keep in mind the teams defense, division and home park to try to really evaluate a player. FIP and xFIP are a guideline just like ERA is, none of them are all that valuable by themselves.