Felipe Vazquez

Formerly Felipe Rivero, Vazquez recovered from an early forearm scare and some struggles on the field to save a career-high 37 games while posting a 2.70 ERA. That latter figure was up more than a run from the pristine 1.67 ERA he posted the season prior, but that can likely be chalked up mostly to a 97-point jump in his opponents' BABIP, up from .234 in 2017 to .331 last season. His true talent likely lies somewhere in the middle. His 2.43 FIP was a near match for the 2.47 figure he posted the year before. After posting a career-best 30.1% strikeout rate, Vazquez is entrenched as the Pirates' closer and as a clear top-10 fantasy stopper. The Pirates could be well out the race at the deadline, but Vazquez is under control through 2023 and so a trade seems pretty unlikely, though not completely out of the question. Of course, if he pitches as expected, he could continue to save games even if he were traded.

Acquired from Washington in the 2016 Mark Melancon trade, Rivero vaulted into the upper echelon of relievers with his performance last season. He added three whole ticks to his fastball (98.5 mph), which pitching coach Ray Searage suggested was a byproduct of a more compact delivery, with Rivero keeping his lead foot underneath his knee. Searage also hinted at a correction of a pitch-tipping issue. The added velocity helped Rivero hit his spots more consistently -- he shaved his walk rate from 3.9 BB/9 to 2.4 -- and made his devastating changeup even more difficult to hit. Rivero averaged 10.5 K/9 and turned in a 2.47 FIP (13th among 355 pitchers with at least 50 innings). He proved plenty capable in the ninth after taking the job from Tony Watson, converting all but two of his 24 save opportunities. The 26-year-old has a case to be a top-five closer off the board.

The Pirates are extremely high on Rivero, and there's talk he could close if Tony Watson falters or is traded. Acquired as part of the Mark Melancon deadline deal, the 26-year-old southpaw throws easy gas, averaging 95.8 mph with his heater. Oddly, Rivero's splits against left-handed hitters (.286/.387/.378) and righties (.203/.290/.337) go against conventional thinking. In any case, there's thought that he could fill an Andrew Miller-like role, throwing multiple high-leverage innings. Pittsburgh and pitching coach Ray Searage have found success molding relievers into closers, and it wouldn't be surprising to see Rivero follow in the footsteps of Joel Hanrahan and Jason Grilli. He will come fairly cheap on draft day, and should be able to offer solid ratios while owners hope for an opening in the ninth inning role.

One of the few bright spots in the Nationals' bullpen last year, Rivero's season very nearly ended before it began after he was hospitalized with a burst ulcer in his stomach in April. Surgery and a slow recovery kept him out of the majors for six weeks, but once he rejoined the bullpen he did his best to make up for the lost time, posting a 12:2 K:BB ratio in 10.1 June innings. By the end of the year, after both Drew Storen and Jonathan Papelbon had taken themselves out of the picture, Rivero found himself in the closer role and picked up his first two big league saves. A left-hander with a big fastball and solid slider, he was almost as tough on righties (.198/.255/.344) as he was on lefties (.198/.242/.244), which could give him an inside track on retaining the closer job in 2016. Both Papelbon and Storen are still Nats property heading into the offseason, however, so it's more likely that Rivero finds himself as a set-up man in 2016.

At this point, Rivero is purely a wild card as far as prospects go. Acquired from the Rays in the Nate Karns deal before the start of the 2014 season, the skinny left-hander struggled to stay healthy last year. When he was on the field he battled the same control issues he faced in the Tampa organization. His raw stuff is eye-opening, and lefties with mid-90s heat, sharp curves and workable changeups will keep getting chances to put it all together long past the point when it's obvious they won't. Barring a catastrophic injury or development spike that carries him all the way to the major league bullpen, Rivero will have a permanent spot on Nationals' top prospect lists for the foreseeable future.

Rivero has been worked slowly in the Rays' organization, spending a full season at each stop along the way. He was productive in 2013 with High-A Charlotte, pitching in 25 games with 23 of those being starts. The southpaw is known to have a solid fastball, despite his thin frame (6'0", 150). He also confidently mixes in his secondary pitches, though they are thought to need some development before he can reach the majors. He posted a 3.40 ERA, which included two shutouts and 91 strikeouts in 127 innings. His walk rate increased slightly last season, but it seems likely he will spend most of the 2014 season one rung up the ladder with Double-A Montgomery.