Relief Pitcher Prospect Rankings (May) - 2018 Impact Rookies

The nature of relief pitchers is such that it is nearly impossible to predict with any certainty who will produce at the major league level. Often times, especially in keeper and dynasty leagues, stashing relief pitching prospects is simply not worth the trouble because they rarely contribute in fantasy in the beginning of their career. Yes, every so often we get an Edwin Diaz or a Roberto Osuna, but my guess is that neither of those guys were being stashed with the hope that they would scoop the closer job immediately upon being recalled.

And it is with all of that in mind that I originally refused to write this article. A special shout out must go to my editor, Pierre Camus, for pushing me towards putting this article out. Still, though, I think that this was an extremely difficult article to research and write.

A quick note: I excluded all current major leaguers that are still prospect eligible from this list because I felt that it wouldn't be in the spirit of the article. If all goes well for Jimmie Sherfy, Joe Jimenez, and Seranthony Dominguez, none of them will be prospect eligible at the end of the season. Plus, nearly every seasoned fantasy baseball player knows about these three folks, so while I would prioritize scooping them over anybody on this list, I'm not going to rank them because they are pitching for an MLB team.

Ranking Philosophy

You'll notice that I put two Rays, White Sox, and Padres on this list. That's because this is a fantasy relief pitcher article. The Rays, White Sox, and Padres all have closer situations that are either in flux or relatively likely to be in flux in the near future (assuming the Padres trade Hand at the deadline or during the next offseason). Relievers are a dime a dozen and while guys like Hand don't come along all-too-often, good relievers also sometimes pop up seemingly out of nowhere. So there is more of an emphasis on proximity and potential closing opportunities in these ranks than pure stuff.

Top 10 Relief Pitcher Prospects for 2018 Fantasy Baseball

1. Zack Burdi (CWS, AAA)
Stats: Has not played (Recovering from Tommy John surgery)
ETA: 2019

Burdi was selected by the White Sox in the first round of the 2016 draft with the hope that he would be fast-tracked to the majors. Burdi pitched with four different minor league levels in 2016 (the year he was drafted!) and made it all the way to AAA. In 2017, he opened the year by throwing 33.1 solid-but-not-great innings with AAA and then tore his UCL. Had he not gotten injured, he likely would have made his major league debut last year, but instead we will need to wait until 2019 to see Burdi in big league action.

2. Koda Glover (WSH, AAA)
Stats: Has not played (Recovering from shoulder injury)
ETA: August 2018

Glover and Burdi are similar in a lot of ways. Both of them were drafted and then put on the fast track to the majors. The difference between the two of them is that Glover actually made it all the way to the Show before getting injured. In his time as a big leaguer, Glover has a relatively uninspiring 5.08 ERA but that comes with a much more palatable 1.179 WHIP, 7.6 K/9 and 3.72 FIP. Last season, Glover pitched to a 5.12 ERA over 19.1 innings, but his peripherals indicate he got unlucky: 2.69 FIP, 3.86 xFIP, 3.66 SIERA. Plus, Glover had a 7.9 K/9 and a 1.9 BB/9. His strand rate was 57.5%, extremely low and mostly a result of poor luck. Glover will be in the cards to close in Washington soon-ish, but Doolittle is under contract until the end of 2020 if he has all his options picked up, so Glover may have to get traded to get a shot at the ninth.

3. Thyago Vieira (CWS, AAA)
Stats: 22.2 IP, 35 K, 21 BB, 5.16 ERA, 1.76 WHIP, 40.8% GB%
ETA: August 2018

It's very possible that Vieira does not get the call to the majors this year. There is no need for the White Sox to lose service time on a player that will likely be a stalwart at the back of the team's pen during their contention cycle (it's coming guys, don't worry). With that being said, Vieira has a very problematic 8.3 BB/9 this season. He has not struggled like this since he was back in A-ball in 2015, so I have faith that this is just a blip on the radar. If it's not, however, Vieira might be best remembered for throwing his first ever warm-up pitch as a big leaguer to the backstop instead of a solid relief pitcher who closed out a handful of games during his career.

4. Diego Castillo (TB, AAA)
Stats: 24.1 IP, 27 K, 6 BB, 0.74 ERA, 0.78 WHIP, 60.0% GB%
ETA: July 2018

Knowing how the Kevin Cash manages the Rays bullpen, Castillo could very well be recalled to the major leagues tomorrow. The slight issue with that is that Castillo isn't on the Rays 40-man roster, but that is an obstacle that can be easily overcome, especially for someone of Castillo's talent level. At his best, Castillo has a lethal fastball-slider combo with a heater that touches triple digits and a slider that completely fools hitters. The slight issue is that he is 24 years old which would put him on the older side for any prospect. We are looking at relief pitching prospects here, though, and if Castillo gets a shot in the Rays bullpen this year he is nearly guaranteed to at least see a few save opportunities.

5. Colin Poche (TB, AAA)
AA Stats: 16.0 IP, 32 K, 2 BB, 0.00 ERA, 0.38 WHIP, 15.8% GB%
AAA Stats: 11.1 IP, 20 K, 4 BB, 1.59 ERA, 1.06 WHIP, 33.3% GB%
ETA: July 2018

Poche and his teammate Castillo could both be in the mix for saves later in the season in Tampa Bay. Relief pitching prospects do not get a lot of love, and with good reason, but Poche is on another level of dominance in the minor leagues this year. Through 27 minor league innings across two levels, Poche has struck out well over 50% of the batters he has faced this year. Like Castillo, Poche is not on the forty-man roster, but if he continues to pitch as well has he has he could be the next man up in the event that the Rays need bullpen reinforcements. The best part about Poche, for the Rays, is that he was the PTBNL in the Souza deal. He was not even the main part of the deal and the Rays may have a relief ace on their hands. That's a job well done by the scouting department.

6. Dillon Maples (CHC, AAA)
Stats: 15.2 IP, 24 K, 18 BB, 5.17 ERA, 1.91 WHIP, 54.5% GB%
ETA: August 2018

The stats aren't encouraging but that is why scouts will tell you nnot to scout the stat line. That may not really apply here, though, as Maples had walk issues whe nhe came to the major leagues in his brief call-up last season. There is a widespread belief that Maples will be back up at some point this season but whether or not he will be an effective late-inning reliever for a Cubs team that will be competing for yet another World Series title or just a mop-up guy remains to be seen. I'm sure the Cubs are hoping for the former, but fantasy owners needn't hope either way; Maples won't be getting a shot at saves any time soon. Yeah, we're at that part of the list.

7. Andres Munoz (SD, A)
Stats: Has not played (elbow injury)
ETA: late 2019

Munoz, assuming his elbow injury is relatively minor for a two-month injury, and that he can return to pitching soon, is a great example of why we sho9uld sometimes pay attention to relief pitching prospects. As an 18-year-old in A-ball last year, Munoz struck out 38 batters in 26 innings, all against competition mostly older than himself. He did have some control issues but that is what comes along with being a young fireballer. There's no need to go run and grab Munoz at the drop of a hat, but he's someone to keep an eye on for possible saves a year or two down the line. The Padres are bound to deal Hand at some point and that bullpen seems pretty wide open.

8. Trey Wingenter (SD, AAA)
Stats: 22.2 IP, 26 K, 12 BB, 3.97 ERA, 1.24 WHIP, 50.9% GB%
ETA: September 2018

Wingenter, talent wise, is not as good as Munoz. That does not matter because the best ability is availability and Wingenter has actually pitched this year; Munoz has not. It's unlikely that Wingenter closes any games for the Padres this year but, again, Hand is not going to be around forever and Wingenter has gotten good results in the upper minors (12.08 K/9 last year in almost 50 innings at AA). His stats have worsened a bit this year but considering that he is pitching in the hitter-friendly Pacific Coast League, I do not see anything to be particularly worried about. Wingenter should be a September call-up and will have the chance to earn a full-time bullpen role in 2019.

9. Jimmy Herget (CIN, AAA)
Stats: 22.0 IP, 23 K, 8 BB, 3.27 ERA, 1.36 WHIP, 28.6% GB%
ETA: July 2018

Herget is a flyball pitcher that will fit in perfectly with the rest of the staff in the big leagues that is prone to giving up homers. I'm kidding (mostly). Herget is a sidearmer who sits in the low 90s and has a nasty slider that he has used as his out pitch in the minor leagues. The issue with sidearmers is that they tend to have extreme platoon splits. That being said, Steve Cishek is a notable sidearmer who has had success in the late innings, so Herget could follow the Cishek path and end up closing in Cincinnati. It's not as though he has a lot of competition if Raisel Iglesias is traded.

10. Branden Kline (BAL, AA)
A Stats: 20.2 IP, 23 K, 3 BB, 1.31 ERA, 1.11 WHIP, 35.7% GB%
AA Stats: 7.1 IP, 6 SO, 4 BB, 2.45 ERA, 1.09 WHIP, 45.0% GB%
ETA: Mid 2019

Kline is honestly a huge dart throw. He's on the list because I think he has an outside shot at closing for the Orioles once Britton's contract ends. The Orioles would more likely go with Brach or O'Day than a pitched struggling to adjust in AA, but Kline was once one of the better prospects in the Orioles system so the pedigree is there. He was a high second round draft pick and we have seen crazier things than a second rounder finally figuring it out after seven years in the minor leagues. Plus, Kline is working his way back from injury, so if he's finally healthy for the first time in a long time that could bode well for him. I'm not expecting Kline to give us the world, or even anything of value, but there are really not a whole lot of very interesting relief prospects in the minors so he gets the nod for the ten spot.

More 2018 MLB Prospects Analysis