And this is where DIPS theory really breaks down for a lot of people. If we tell someone that Lincecum has just been unlucky, and then they watch him throw those pitches, they’re not going to agree with you, and they probably shouldn’t. The word luck undermines the actual point of DIPS, which is not that the pitcher has no control over the outcome of a ball in play, but that variations in outcomes on balls in play don’t tell us much about what to expect from a pitcher’s future outcomes on balls in play. It’s not so much about being lucky as it is about doing something that isn’t likely to repeat in future. It’s more about repeatability or sustainability than what most people consider to be luck.
Saying that Tim Lincecum has been unlucky is probably not true. He’s struggling with his command, falling behind in counts more often, and throwing pitches that are rightfully getting crushed based on movement and location. If Wells had fouled off that fastball on Saturday, that would have been luck, so maybe you could argue that Lincecum is suffering from a lack of good luck (in that it’s quite possible that hitters aren’t missing his mistakes as often as they used to), but that’s not the same thing as suffering from bad luck.