Milwaukee's Marco Estrada is the worst. Well, he's not the worst, but that's actually a big part of the problem.
In 2012 and '13, Estrada posted a 3.75/1.11 line with an 8.8 K/9 ratio. Pretty good, right? There was one black mark -- a 1.25 HR ratio -- but that was palatable given his low BB-rate (1.96).
This year, it's all spun out of control. Estrada has allowed at least one homer in all but one game, giving him a total of 20, or 2.28 every nine innings. His BB-rate has also risen above 3.0. It's all resulted in a 4.56 ERA that he's actually lucky to have (5.67 FIP). His rotation spot is in jeopardy, but obviously you don't want a gopher-baller entering in key relief situations. If Estrada gets removed from the rotation, is there really a point to having him on a major league roster?
For fantasy purposes, the problem with Estrada is that he pitches in a hitters park. You'll never feel comfortable with him at home, and a good chunk of the road parks are going to be potential landmines, too. So, you're basically saving him for favorable matchups on the road, like, say, facing the Mets in New York. Oh, wait, that's where he pitched last night when he gave up six runs -- including a grand slam to Taylor Teagarden after walking the bases loaded -- in just six innings.
Yeah, there's really no situation in which you can trust Estrada.
But, assuming Estrada wasn't such a boob, there are ways to determine the matchups in which you can trust him or other homer-happy pitchers. First, check a team's HR numbers -- not all good offenses hit a ton of bombs (Dodgers), and not all bad offenses can't put 'em in the stands (Astros) -- then, check a ballpark's HRs allowed. Fantasy Source happens to have an easy way to check both with our Team Offense chart and Ballpark stats page.
If you find a decent mix, you can take shots on Trevor Bauer, Jake Peavy, Jaime Garcia or Wade Miley. Those pitchers aren't perfect, but if you can neutralize their HR problems, they're a lot better and worthy of spot starts.
As for Estrada, well, he probably needs a minor league rehab assignment to "clear his head." Until that happens, starting him -- anywhere -- is the worst possible decision you could make.