Since the Miami Marlins traded a few pitchers of interest in the offseason, they were forced to acquire a few more as a result. They got the lower end of the deal pitching-wise in grabbing Dan Haren in the Los Angeles Dodgers trade that also netted Dee Gordon and acquiring David Phelps as part of the Martin Prado trade, but both of these players were expected at best to be back-end rotation options.
Thanks to a myriad of injuries, however, the Marlins ended up needing all of their innings to fill gaps in their dwindling rotation.
For a free pickup from the Dodgers as part of that trade, the Marlins could have done worse than Haren. While Baseball-Reference gave him a lot of credit for his 3.42 ERA with the team, the more conservative estimates of Haren's value seem more likely. In those, it seems he put up around 0.7 wins in 129 innings, which would have been good for about a win in a full season. That is essentially what was expected of him, so the Marlins cannot really complain.
As Haren has been doing for quite some time, his control of the strike zone was once again impeccable. His 16.8 percent strikeout rate was still the lowest he had posted since 2004, but at least he barely walked anyone; by the end of the 2015 season, only 10 pitchers had walked batters at a lower rate than Haren at five percent. That control kept him in games and was the only way he had to keep baserunners off of the paths. Luckily, for Haren, Miami's defense helped him to a .248 BABIP, which aided his already classically low BABIP marks.
The only problem with Haren was that the home run issue that has plagued him since 2012 has continued with a vengeance. Even in moving to a new stadium with deep dimensions, Haren still coughed up 25 home runs in 129 innings, a mammoth total. Those 25 homers would have ranked 13th in baseball among highest home run totals allowed had Haren ended his season in Miami at the time. To be fair, those homers came disproportionately away from Miami, as he gave up 21 of his 31 total homers on the road.
That home run issue just could not be resolved, and that is likely because Haren's stuff is drastically weaker now. His fastball was traveling at an average of 86.9 mph, which is among the slowest pitches in baseball. Haren had only more gas than Mark Buehrle, who is seemingly a metronome, and R.A. Dickey, who throws a knuckleball. Without the trickery of either man, Haren is increasingly throwing junkball stuff not fitted for the bigs.
Phelps was acquired in the Nathan Eovaldi - Martin Prado trade as additional pitching depth. The Marlins curiously acquired a guy who had not established himself as a starter and was supposed to earn arbitration for the first time, making the addition a puzzling one to say the least. Phelps was expected to at best compete for the fifth starter spot, but he worked his way initially into a bullpen role after a strong Spring Training.
He was pressed into regular duty early on, making only four relief appearances all year. Henderson Alvarez hit the disabled list and the Marlins promoted Phelps first before anyone else, and early on they got decent returns from the righty. Despite his middling stuff, he was getting just enough strikeouts and avoiding just enough walks to be a passable player, and combined with the rest of the Marlins struggling, it looked like Phelps was almost performing well. Through two months, he had a respectable 3.50 ERA and 3.47 FIP. However, he had only allowed three homers in those first few innings, and a guy with a 42 percent ground ball rate cannot keep up that performance.
Sure enough, he gave up four home runs in June en route to a 5.68 ERA and 4.71 FIP, and that tainted the rest of his otherwise decent, if unspectacular year. Phelps went through July with a passable performance again buoyed by a paucity of home runs allowed, before losing the rest of his year with a stress fracture of the radial head near his elbow.
In the end, the Marlins essentially got what they should have expected from Phelps, which was essentially a Tom Koehler substitute with lesser stuff. Phelps threw a cutter and a curve primarily as his secondary offerings along with a changeup and a fastball, but the fastball averaged just 91 mph to Koehler's 92 mph stuff. In addition, none of Phelps's stuff missed bats all that often, with no pitch going over a 20 percent whiff rate per swing. With low whiff rates, low ground ball rates, and mediocre stuff, the Fish should not be surprised at Phelps's 2015 results.