Rick Lucks previews the fantasy prospects of Brad Boxberger and Welington Castillo to determine whether they will help fantasy baseball rosters in 2018.

The hot stove has been more of an ice box so far this season, as few moves have been made of any fantasy consequence. This seems poised to change in the near future, as both Shohei Ohtani and Giancarlo Stanton should provide some clarity regarding their intentions before the new year.

That said, the two players below have the upside to help win a fantasy title if they slip under the radar on draft day. Brad Boxberger becomes an intriguing speculative saves play in Arizona, while Welington Castillo could be one of the best catchers in fantasy.

Let's take a closer look, shall we?

• Fantasy baseball trade analyzer
• BvP matchups data (Batter vs. Pitcher)
• PvB matchups data (Pitcher vs. Batter)
• Who should I start? Fantasy baseball comparisons
• Daily MLB starting lineups
• Fantasy baseball closer depth charts
• Fantasy Baseball live scoreboard
• Fantasy baseball injury reports

The Fantasy Jury is Out

Brad Boxberger (RP, ARI)

Boxberger only pitched 29 1/3 innings last season due to a variety of lat and forearm ailments, but he made them count with a 3.38 ERA (3.36 xFIP) and 33.1% K% in that time frame. Arizona's closer last year was the consistently unappealing Fernando Rodney, leaving the ninth inning role available even if the team decides to bring back the incumbent.

Closers generally need two things to succeed: strikeout stuff and no obvious weaknesses. Boxberger generated his Ks last year with a three-pitch mix: a well above average fastball (11.9% SwStr%, 57.7% Zone%), solid change (13.9% SwStr%, 33.8% Zone%, 38.6% chase rate), and mediocre slider (9% SwStr%, 44.9% Zone%, 23.3% chase rate). Boxberger used his fastball 67.1% of the time last year, so he seems to understand that it's his best pitch. The change also has a reasonable chase rate despite a low Zone%, suggesting that it has a future as a put away pitch. The slider is nothing more than a show-me offering.

Overall, this repertoire seems safe to project a healthy number of Ks for. Boxberger's preference for his change (20.8% usage) over his slider (12.2%) has also allowed the right-handed pitcher to fare well against lefties (.189/.282/.319) over his career, preventing opposing managers from exploiting the platoon advantage in high-leverage situations.

He also had identical 3.38 ERA marks at home and on the road last season, with a mild split (3.02 home vs. 3.40 road) over his career. Considering he called the only pitcher's park in the AL East home for his entire career before heading to the desert, Boxberger seems capable of handling any stadium. Thus, Boxberger has the stuff and lack of weaknesses necessary to thrive in the ninth inning.

Perhaps the biggest obstacle in Boxberger's way is teammate Archie Bradley, who recorded a 1.73 ERA and 27.2% K% over 73 IP last season. Bradley might be a better pitcher than Boxberger, but he is no lock for the ninth. First of all, Arizona is probably not interested in paying Bradley closer arbitration salaries. The team wouldn't want to pay Boxberger any more than they need to either, but he already has a 41-Save season to his credit (2015). The team gets greater payroll flexibility by allowing the guy with saves to get more of them instead of paying two arbitration-eligible closers.

Boxberger's checkered health history is also notable. The aforementioned lat and forearm injuries kept Boxberger shelved until June 20 last season, and he missed even more time in 2016 with a torn adductor brevis muscle and strained oblique muscle. It seems likely that he could benefit from a closer's predictable workload, seldom warming up before the eighth inning. By contrast, shoehorning Bradley into the ninth likely prevents him from matching last year's innings total. Boxberger probably can't throw that many innings in a set-up role either, forcing Arizona to rely more on their second-tier arms.

Thus, Arizona saves money while maximizing the workloads of their high leverage arms by using Boxberger to close over Bradley. Boxberger's 30.7% career K% is high enough to interest fantasy owners, and he's succeeded in the ninth before. There will be few superior speculative closers available on draft day.

Verdict: Champ

Welington Castillo (C, CWS)

Castillo quietly put up an excellent fantasy campaign in 2017, slashing .282/.323/.490 with 20 dingers in only 365 PAs. Catchers are typically terrible hitters, making it a premium position in the fantasy game. Anybody who doesn't actively hurt you is generally considered an asset, and Castillo legitimately contributed.

Castillo's .336 BABIP seems high for a slow-footed catcher, causing some to project a lower average moving forward. It wasn't as much of a fluke as you might think, however, as Castillo has a .318 career BABIP over 2,269 career PAs. He's not fast, but an all-fields approach (52.6% Pull% on GB last year) allows him to beat the shift (.315 in 73 PAs) and produce league average production on ground balls (.247 BABIP last year, .232 career).

Castillo has also developed a line drive swing, following up 2016's 25.4% LD% with a 24.4% mark last year. He had no history of hitting line drives before 2016 (18.4% in 2015, 21.5% career), and the stat is notorious for random fluctuations. Still, we're talking about a catcher with a realistic chance to be undervalued on draft day. Those aren't exactly in abundant supply.

Castillo's pop seems fluky at first glance too, as his HR/FB surged from 14.3% in 2016 to 22.5% last year. His career rate (14.5%) is virtually identical to his 2016 production, and he didn't pull any more fly balls last year (22.5%) than he has over his career (21%). He also hit 13 of his 20 bombs at hitter-friendly Camden Yards, a stadium with a 111 HR factor for right-handed batters last year according to Baseball Prospectus.

On the bright side, Castillo hit more fly balls (36.2% FB% vs. 32.8% in 2016) and is moving to another park that boosts right-handed power (104 HR factor last year). His average airborne exit velocity (92.1 mph to 93.6) and rate of Brls/BBE (6% to 10.2%) also improved significantly last year relative to the year before, suggesting at least some real power growth.

The rebuilding White Sox could also be a fertile place for the veteran catcher. The team has nobody with name recognition in their lineup besides Jose Abreu, and he's rumored to be on the trade block. They probably don't want to put any additional pressure on young guys like Yoan Moncada, so any veterans on the roster are likely to occupy prime lineup spots while the kids grow up. He might even get to DH when he needs a day off behind the plate, compiling more PAs than your average catcher.

Castillo represents an interesting buying opportunity in 2018. He won't hit the 40 HR his 2017 line prorates to as he's more of a 25-HR guy with an acceptable batting average. Were your catchers that good last year? No? Are players on bad teams typically undervalued in your league? If so, Castillo may be the kind of under the radar addition that positions your squad to finish in the money.

Verdict: Champ

More 2018 Player Outlooks

Premium Tools & DFS Research

Get a free trial of our powerful MLB Premium Tools. Our famous DFS Optimizer & Lineup Generator, daily Matchup Ratings, expert DFS Lineups/Cheat Sheets, and more.

Sign Up Now!