I love middle relievers in fantasy baseball. I play in a lot of deeper formats where they are viable as staff supplements even if Holds isn’t a category so I’m always looking out for the next big thing. I’m not completely averse to buying a Josh Hader (although that might be a bad example this year as he’s been the de facto closer with Corey Knebel out for the year and Jeremy Jeffress yet to debut), Dellin Betances, or this year’s draft darling, Ryan Pressly, but a major key to the value of middle relievers is that they’re cheap. Finding the next Hader, Betances, or Pressly is much more useful and can often be done on the fly in-season.
With today’s tattered starting pitcher landscape, middle relievers are as popular as ever, so we need to get the jump on the next big thing since more eyes are searching for them. It’s only April 16th so reliever samples are especially small as only 20 guys have even 10 innings, but I’ve still got my eye on 10 middle men who could help stop the bleeding for those of us toting the obscene ERAs of Carlos Carrasco (12.60), Nick Pivetta (9.45), Chris Sale (9.00), Walker Buehler (8.25), Zack Wheeler (7.47), Aaron Nola (7.45), Corey Kluber (6.16), and more. Some of these guys could even become their team’s closer which would only add to their fantasy value, but that is not a major consideration for this list.
Diego Castillo, TB | 30% K, 10% BB, 14% SwStr, .111 AVG in 9 IP
Castillo is part of a 1-2 punch at the backend of Tampa Bay’s bullpen with closer Jose Alvarado. The righty/lefty duo (Castillo being the righty) had strong seasons in 2018, too, and came into the season battling for the closer’s role. Alvarado won out, but Castillo is a key part of the bridge to the ninth and has already nabbed five Holds in his eight appearances.
He’s essentially matching the skills we saw in his 56.7 innings last year with a slightly higher walk rate, though we are still very much in the range where a walk-free outing or two-walk outing can greatly change the rate. Castillo may steal a few saves (he’s already gotten one) along the way in situations where the Rays are facing a righty-heavy 9th inning and/or Alvarado isn’t available. He’s likely not available in Holds leagues, but in other leagues where middle relievers are useful, he’s one to target.
Lou Trivino, OAK | 33% K, 3% BB, 14% SwStr, .158 AVG in 11 IP
I thought Trivino might become this year’s MRP draft darling, but Pressly snagged that role and ran with it. He was a key piece in the awesome Oakland bullpen from last year, riding an elite cutter to an excellent 74-inning season. That cutter is instrumental in his strikeout rate while a 98-mph fastball and 80-mph curveball give him three worthwhile offerings. He’s using the curve a bit more this year, jumping 8 points to 15% usage.
Trivino has boosted his Zone rate 10 points to 54% and is garnering first-pitch strikes at a 64% clip (+9 from last year), helping tamp his walk rate down from last year’s 10% mark. His chase rate is also up two ticks to 37%. He remains instrumental at the backend of Oakland’s pen, though he’s likely third in line for saves behind current closer Blake Treinen and setup man Joakim Soria.
Nick Burdi, PIT | 48% K, 4% BB, 22% SwStr, .231 AVG in 6.7 IP
Burdi is a former 2nd rounder from the Twins that made his way to Pittsburgh via the Rule 5 draft. The Phillies drafted him in the winter of 2017 and then flipped him to the Pirates. After spending the bulk of 2018 returning from Tommy John surgery, it now looks like that pick might’ve been a hidden gem.
Parsing an already tiny 6.7-inning sample is kind of silly, but after a rough series against St. Louis (3 ER in just two-thirds of an inning over two outings), Burdi has been excellent the last week-plus. He has fanned eight of the 17 batters faced in five scoreless innings, featuring an 88-mph slider and 97-mph fastball. We’ll see if he continues this setup, but so far he’s thrown the slider 57% of the time and backing it up with the fastball (43% of time… obviously).
He hasn’t really come close to a full season as a pro so the 26-year old righty is essentially learning on the job, but he seems rather capable of being an impact reliever. He’s still under Rule 5 restrictions since he threw just an inning and a third with the Pirates last year so he’s going to get his chances to succeed. Keone Kela and Richard Rodriguez would likely be next in line if the Pirates fell out of contention and dealt Felipe Vazquez, but Burdi could push 100 strikeouts in a 60-65 inning season if his slider continues trip up the opposition like this.
Nick Anderson, MIA | 49% K, 6% BB, 19% SwStr, .233 AVG in 7.7 IP
A trade pickup from Minnesota this past winter, Anderson has been a standout rookie reliever for the lowly Marlins. His fastball-slider combo has yielded seven straight multi-strikeout appearances after a two-pitch one out appearance on Opening Day. The backend of the Marlins bullpen is a mess as neither Drew Steckenrider nor Sergio Romo has really grabbed hold of the closer’s role and my favorite, Adam Conley, hasn’t taken off as I’d hoped just yet. So not only is Anderson capable of being a strikeout and ratio stud, but he could soon overtake the ninth inning role and net some saves. He obviously won’t get a ton in Miami, but they are an ancillary benefit anyway so I’m not too worried about it.
Robert Stephenson, CIN | 38% K, 3% BB, 18% SwStr, .097 AVG in 9.3 IP
The former 1st rounder has never been able to command his stuff regularly enough to be a viable starter, in the minors or majors. In 133 major league innings, he had just a 7% K-BB rate (thanks in large part to a 14% BB rate) en route to a 5.47 ERA and 1.67 WHIP. Now in the bullpen, Stephenson is leaning on his slider at a 54% clip and backing it up with a mid-90s fastball (39% usage) and seldom-used changeup (7%).
The slider is generating a 31% swinging strike rate, third among the 103 pitchers with at least 50 thrown. The aforementioned Nick Burdi is first at 34% and starter Corbin Burnes sits second at 33%. Four of Stephenson’s six outings have gone beyond an inning and it’d be great to see the Reds let him push 100 innings as a super reliever. That kind of volume could make a major asset in many league formats, especially if he continues pitch at or near the level we’ve seen early on. He could be one of my favorites this year.
Ty Buttrey, LAA | 41% K, 0% BB, 19% SwStr, .227 AVG in 6 IP
Buttrey didn’t debut until mid-August of last year, but he really hit the ground running. Had he not allowed five runs in his final two appearances (totaling one inning), his results might’ve stood out more. In the 15.3 innings before those last two appearances, he put up 0.59 ERA and 0.92 WHIP with a 32% K rate and 7% BB rate. He even nabbed four saves and six holds during that run.
He has hit the ground running in 2019 as Cody Allen’s setup man, striking out nine and not walking anyone in six scoreless innings. He generates plenty of whiffs with both his fastball (96 mph) and slider (83 mph) and even mixes in a show-me changeup. He’s only used it 9% of the time so far, but it was at 17% last year so he might even rely upon it more as the season goes on. Allen has also been solid, but he’s lost another tick on his fastball and he obviously won’t sustain a .067 BABIP so if he pitches more like 2018, Buttrey could be back in the ninth inning and wind up as a solid closer.
Reyes Moronta, SF | 42% K, 7% BB, 13% SwStr, .172 AVG in 7.7 IP
In his first 14 outings of 2018, Moronta did strike out 14 batters, but also walked 13. Over his final 55 appearances, he had 65 strikeouts and 24 walks (34% K, 12% BB) and became a key piece in the Giants bullpen. He’s been even better to start 2019. He opened this season with five strikeouts in a 2-inning outing and has logged a strikeout in six of his seven appearances. That said, the improved walk rate has come with an improved first-pitch strike rate or much of a jump in his zone rate (+2.2 points to 44.4%) so I suspect he’ll meander back toward a double-digit rate. Of course, if he fans a third of the batters he’s facing and continues to allow hits at the 4.8 per clip we’ve seen since the start of 2018, then a few extra walks shouldn’t be an issue.
Adam Morgan, PHI | 29% K, 0% BB, 17% SwStr, .125 AVG in 7.3 IP
Morgan is looking to become the key lefty in Phillies bullpen and doing a great job of it so far this year. Focusing on two breaking balls and a changeup (a very nice 69% usage for the three pitches) has yielded seven and a third scoreless and walk-free innings along with a strong 29% strikeout rate. He’s logged a first-pitch strike against three-fourths of his batters faced while netting a league-best 48% chase rate (min. 5 IP). Morgan also has four holds and a win in his eight appearances.
Trevor Hildenberger, MIN | 41% K, 5% BB, 18% SwStr, .200 AVG in 5.3 IP
Despite making eight appearances, Hildenberger has just 5.3 innings of work with five of his outings falling short of an inning. They let him work more than an inning in 15 of his 73 outings last year, so hopefully they expand his role a bit as the season goes on. He isn’t a power arm like most of this list, throwing just 89 mph with his fastball, but he has three reliable pitches with a changeup (34%) and slider (28%) that get plenty of run. His 13% SwStr from last year could’ve easily netted a strikeout rate better than the 22% he had, perhaps something in line with his 26% in 2017. I doubt he maintains a 41% K rate, but he could push 30% if he holds some of the swinging strike gains.
Tayron Guerrero, MIA | 29% K, 16% BB, 23% SwStr, .120 AVG in 7.7 IP
Guerrero is one of the league’s hardest throwers, but he’s also one of the wildest. He doesn’t necessarily need to maintain a .188 BABIP to stifle hits, but he can’t sustain his .339 career mark and maintain a fantasy-viable WHIP. Guerrero has only allowed three hits so far this year, but also walked a batter in each of his last five outings. If he can keep missing bats with his blazing 98-mph fastball and 87-mph slider, then he can overcome the walks.