Deals have been coming in fast and furious, giving fantasy owners a lot of things to consider. A lot of the moves have centered on relievers thus far, with Sean Doolittle looking like a Champ after debuting for the Nationals in a save situation last Tuesday night. Ryan Madson appears to be his set-up guy, making him a Chump in most formats. David Robertson and Tommy Kahnle join him on the Chump list, as Robertson lost save opportunities while Kahnle failed to gain them.

The Yankees also acquired Todd Frazier in their trade with the White Sox, allowing the latter club to call up the consensus top prospect in the game: Yoan Moncada. Arizona also acquired slugger J.D. Martinez in a deal that feels like somewhat of a surprise. These players do not rely on one situational statistic to produce fantasy value, so let's take a closer look to determine what fantasy owners should expect from them moving forward.

Ownership rates provided are from Yahoo leagues.

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The Fantasy Jury is Out

Yoan Moncada (3B, CWS) 56% Owned

Moncada has all of 20 MLB plate appearances, so we're working with minor league data here. He's slashing .282/.377/.447 with 12 HR and 17 SB in 361 PAs at Triple-A, numbers capable of making most fantasy owners drool. Last season was arguably even more tantalizing, as Moncada swiped 45 bags with 15 dingers in 491 PAs split between High-A (284 PAs) and Double-A (207). He could be among the more valuable fantasy assets for the next decade if he replicates these numbers at the MLB level.

The upside is elite, but he is far from a sure thing to put it all together this year. To start, his stolen base success rate has plummeted this season. Moncada was caught 12 times last year, producing a success rate of approximately 79%. He has eight CS to go with his 17 SB this year, a success rate of 68%. The White Sox will probably let him run because they have nothing to lose, but a success rate of at least 70% is generally required to get a green light at the highest level.

Moncada's 36.8% FB% at Triple-A is around average, but it represents a professional best for him. His other campaigns have hovered around the 30% mark, a rate that would make it challenging for Moncada to hit for the power many of his owners are expecting. His batting average could also be a liability, as his 28.3% K% at Triple-A is actually an improvement over his 30.9% mark at Double-A last season. Moncada is willing to take a walk (13.6% BB% this year), but there is a ton of swing and miss in his game.

Moncada has maintained reasonable batting averages in the minors thanks to extremely high BABIPs, but they don't always transfer to the Show. His .379 BABIP at Triple-A is partially rooted in a LD% of 26.4%, a rate rarely sustainable at the highest level. Moncada posted a 27.9% LD% at Double-A and a 28.6% mark at High-A, however, creating the possibility of his having a true line drive swing. He also has above average wheels, creating the possibility of overperforming on his ground balls. Still, a .360+ BABIP should not be the expectation.

Moncada also pops up too often (14.9% IFFB% this year, 16.1% at Double-A last year). This will take a big bite out of his BABIP, especially if the increase in FB% proves sustainable. The White Sox are also unlikely to challenge their premium prospect with an important lineup slot right away, potentially leaving him lacking in R and RBI. The upside here is great enough to roster in nearly any format, but any team that doesn't need a miracle to finish in the money might want to start him on the bench, or even trade him while the hype is at its highest.

Verdict: Chump

 
J.D. Martinez (OF, ARI) 96% Owned

Martinez has been one of the top sluggers in the game this year, posting a .305/.388/.630 line with 16 HR in just 232 PAs. The pop is relatively new, as he had only 22 big flies in 517 PAs last year. Martinez has not joined the fly ball revolution, as his 37.6% FB% is virtually identical to last season's 36.2% mark. Instead, his HR/FB has surged from 18% last year to 28.6% this.

Many of his power indicators are moving in the right direction, but not by enough to support an elite HR/FB. Martinez is pulling more of his flies relative to last season, 19.3% to 13.9%. His average airborne exit velocity and rate of Brls/BBE have also increased, going from 96.1 mph to 97.2 and 14.2% to 16.1% respectively. Much of the damage thus far has come against lefties, whom Martinez is crushing for a .474/.556/1.105 line with six of his 16 dingers in just 45 PAs. Martinez does not have a massive career platoon split, so he probably will not continue to destroy lefties to this degree.

Chase Field will likely inflate his HR total from what it would have been in Detroit, but this will translate into more of the same rather than the new level some are projecting. This is fine, as Martinez's current production has been great for fantasy. He is currently on pace for around 45 homers over a full season of PAs, and his average is actually a plus instead of the liability typically seen from elite sluggers.

The strong average is supported by a .338 BABIP right in line with his career .343 mark. Unlike many sluggers, Martinez does not pull an obscene number of grounders (56.3% this season). This allows him to hit .290 against the shift, supporting a .284 career BABIP on grounders (.281 this year). He has also been relatively unlucky on liners this year as measured by both quality (.645 BABIP vs. .715 career) and quantity (20.8% LD% vs. 21.6% career). Add in a 12.8% SwStr% that would be his best showing since 2012, and you get a guy who could actually see his average increase a little moving forward.

Martinez is among the top hitters in the game today. He's probably not available right now in anything other than NL-Only leagues, but he's worth waiver priority and/or all of your FAAB to acquire in those formats.

Verdict: Champ

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