Drafted in the third round of the 2009 MLB Draft by the Texas Rangers, left-hander Robbie Erlin was once a pretty highly regarded college prospect. Following the draft, Erlin threw only four innings in rookie ball in 2009. Erlin started the 2010 season in Low-A and threw over 114 innings split between time as a starter and reliever. Not only did Erlin have a fantastic K-BB ratio (125:17), but he also sported one of the best ERAs at that level at 2.12. Erlin matched his strong Low-A performance to start the 2011 season off in High-A, striking out 62 batters to just five walks in just over 54 innings, this time exclusively as a starter. After 66 innings in Double-A, during which he ran into his first real trouble on the mound, Erlin found himself traded to the Padres as part of the deal that sent right-handed reliever Mike Adams to the Rangers.
Erlin refound his groove following the trade, striking out 31 batters in 26 innings over six starts, with a career-best 1.38 ERA to finish out the year. Going into 2012, all eyes were on Erlin in the Padres’ organization. After a solid start over his first 11 starts back in Double-A, with 72 strikeouts to 14 walks and another ERA in the low twos, Erlin strained his elbow. With continuing elbow issues relating to tendinitis, Erlin didn’t reappear until late in the season in a short stint with the Padres AZL team followed by a stint in the Arizona Fall League.
To begin the 2013 season, Erlin was promoted to Triple-A, where he put up the worst ERA of his career, just over five, in the hitter’s haven that is the Pacific Coast League. Despite his struggles, Erlin made a few relief appearances in April before being promoted to the big league roster to make his big league debut on June 1. After getting a win in his first start, Erlin was optioned back down to Triple-A until he made his return to take Clayton Richard‘s place in the rotation on June 26. After two rough starts, Erlin was sent back down to Triple-A in early July. Erlin ended up back in the big leagues once again at the end of the year, and had some better success. Overall, Erlin finished the year with a 4.12 ERA and 40 strikeouts to 15 walks in 54 and two-thirds innings.
Erlin spent much of his 2014 season in the big leagues with limited success. Following the Padres’ all-in offseason push, Erlin found himself the odd man out of the rotation, so he spent most of 2015 in Triple-A, where he continued to struggle. Following a few rough outings in early 2016, Erlin was diagnosed with a torn UCL in his left arm. He has not pitched since.
Usually, this is where a player’s 2017 performance gets outlined, but for Robbie Erlin there is no performance to look at. So instead, let’s take a look back at Erlin’s arsenal and make some guesses on how his repertoire will look when he returns from injury. Erlin has pretty much always operated as a three-pitch pitcher, although he did use four pitches when he first broke into the big leagues in 2013. From 2013-2015, Erlin pretty consistently used his fastball around 60 percent of the time, with that fastball averaging around 90.5 to 91 mph. Beyond that, Erlin used changeups and curves anywhere between 10-20 percent of the time each, although his usage varied a bit by season. In 2015, for example, Erlin’s changeup usage was higher than ever (21.9 percent) while his curveball was as low as ever (14.6 percent). Erlin upped his changeup usage even more in the early part of 2016, but that may have been due to his UCL injury, which would probably also explain his fastball velocity dipping to an 88.9 average.
Coming back from such a serious injury, it’s hard to know how quickly Erlin’s velocity will come back. More important than that, it will be interesting to see if Erlin keeps a similar pitch mix or switches it up to compensate following the injury.
2018 Projection and Long-Term Outlook
It’s really hard to project any player, let alone someone who is returning from Tommy John surgery. For that reason, I am not even going to try to guess how Erlin will fare in 2018. Given his injury, I don’t think he ends up in the rotation out of spring training. The more likely outcome would probably be Erlin getting back up to speed in Triple-A, or being used as a long relief option out of the bullpen. It’s difficult to imagine the Padres throwing Erlin right to the fire coming off a serious surgery. However, if he can get his velocity back and maintain the feel for his pitches, maybe Erlin can get some time in the backend of the rotation. Either way, at this point in his career, he doesn’t really seem to be an immensely valuable part of the Padres’ rebuild or future plan. But he could surprise us all. The Padres would be wise to leave the door open on that.