RotoBaller's Nick Mariano looks at some fantasy baseball bats for week ten that approach the end of May either extremely hot or cold in the power department.

Welcome back to this investigative piece where we examine players who have seen some notable changes in their power profiles -- for better or for worse -- in 2017.

As usual, you don’t need me to tell you that Miguel Sano or Aaron Judge are strong or that Jarrod Dyson and Billy Hamilton are toward the bottom in average exit velocity. We've passed the two-month mark and are now up to our eyeballs in the waters of the 2017 season.

Identifying top power risers and fallers for each week can help you spot the best pickups before your competition. We'll do the hard work for you, looking at the underlying metrics that influence a hitter's power: fly-ball, pull, hard-hit rates and exit velocity.  Consider buying these week 10 power risers and selling these week 10 power fallers.

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Power Risers

Domingo Santana - (OF, MIL):

In the last two weeks, Santana has once again decided to destroy the ball and turn in a lofty .419 BABIP en route to a .340/.397/.660 slash line. The difference between this streak and his last is that he’s gone yard five times versus the zero count. He’s even chipped in two steals over his most recent four contests, but that’s not why we’re here.

Calling the third most hitter-friendly park home according to ESPN’s Park Factors, Santana has ridden an insane 38.5 percent HR/FB rate thanks in large part to a destructive 52.8 percent hard-hit rate. He’s actually only pulling the ball at a 30.6 percent clip, going the other way most of the time (38.9 percent) instead -- but a 27.8 percent line-drive rate and 36.1 percent fly-ball rate mean he’s sprinkling enough balance around to be hyper-efficient with both his average and his power. It won’t last forever, but his career .347 BABIP and 27 percent HR/FB rate also say the regression shouldn’t be that sharp. A 30/15 season is perfectly attainable, though 25/12 won’t leave one grumpy either.

Lucas Duda - (1B, NYM):

Duda’s season-long .962 OPS checks in at 18^th best in the bigs for hitters with at least 140 plate appearances under their belt, with that figure rising to 1.150 between May 23 and now. So, how has that .400 ISO over the past two weeks or so come to be? Mix in a dash of flies at 38 percent, a smattering of pulling the ball at 54 percent and a heaping helping of hard hits at 58 percent and boom, there you have it.

The 31-year-old looks to be completely healthy and locked in at the plate, but do note that things have been coming back to normal over his last several games. Buoyed more by games prior to June 2, Duda has indeed just hit two of his 16 batted-balls under 93.5 mph since then but hasn’t sent a single one of them over 330 feet since his two-homer game on 6/2. Just something to be aware of if you’re a real intense streak-chaser, but I believe his larger body of work speaks for itself here. 25 owned in Yahoo Leagues is a travesty.

Eduardo Nunez - (SS/3B, SF):

Nunez has been a bat on fire for the past month now, turning in a .365/.384/.542 line with four homers, 18 runs scored, 17 RBIs and nine steals over his last 100 plate appearances (since May 12). But over the last two weeks, he’s been pulling the ball half of the time with an improved 31.3 percent fly-ball rate and solid 27.1 percent hard-hit rate -- which I understand isn’t much, but this is Nunez we’re talking about here.

We have to understand that he’s playing at AT&T Park -- notorious for being pitcher-friendly -- and has the wheels to make grounders work for him, but that doesn’t mean he can’t let the power play in a bit. He won’t top 2016’s 16-homer tally, but 10-12 dingers alongside 40-plus steals and an average floating between .290 and .300 is totally doable here, which is much better than the zero-homer form he had shown up until May 17. Adjust accordingly.

Brett Gardner - (OF, NYY):

Brett “The Hitman” Gardner went without homering over his first 18 games and hasn’t looked back since. The fleet-footed 33-year-old just socked his 13^th homer of the season on Thursday night against Boston and has four long balls and three doubles in his last 11 games. You might not guess it, but his pop has indeed been earned and is not just a product of Yankee Stadium.

Over that 11-game stretch, he’s hit the ball in the air 42 percent of the time, he’s pulled it half of the time and his hard-hit rate sits at 47.4 percent. I’m not going to sit here and act like Yankee Stadium doesn’t help -- especially for a lefty who is pulling the ball -- but do note that his home/road splits are nearly identical (seven homers at home, six away). What’s more telling is his OPS spiking from .693 against lefties to .910 against righties, with a near 20-percent leap in hard-hit rate when he has the advantage. Also doubling is his fly-ball rate. Take this knowledge and deploy it to your liking.

Power Fallers

Salvador Perez - (C, KC):

In case you missed the preseason analyses we ran on these metrics, Salvy popped up on every single one as a riser. From 2015 to 2016, the veteran backstop increased his fly-ball and hard-hit rates by 10 percent and pulled the ball about five percent more, leading to yet another 20-homer season. Well, Perez then shot out of the gates in ’17 to smack four homers in his first six games and had 11 dingers through May 21 (including three across a doubleheader on said date!). Since then? Nada.

While he’s cranked three doubles over his most recent five games and still holds impressive rates in a vacuum, Perez has seen his pull rate sink by 22 percent lately alongside a roughly seven percent dip in both his fly-ball and hard-hit rates. Now, all three marks still sit above 36 percent each so it isn’t as though he’s dead in the water here, but it’s worth taking note for those of you that may be panicking about the 27-year-old’s sudden ceasefire on Souvenir City.

Aledmys Diaz - (SS, STL):

Diaz was going to be a risky buy no matter what considering we had seen basically nothing out of him outside of that incredible 2016 rookie season. He seemingly assuaged most doubt by slapping two homers on April 8 and had slugged five homers through May 1, so things seemed to be lining up well for a similar sophomore campaign for the 26-year-old. While the hits kept coming through May, the power hasn’t been translating -- let’s see if there’s a reason.

We’ll be as fair as can be and go back through May 21 to include a five-game stretch where he clubbed six doubles and see what the math says. 34.1 percent fly-ball rate, not bad. 52.3 percent pull rate, great! 18.2 percent hard-hit rate, oh. Now, after that stretch begins his true “last 14 days” window, and within that he hasn’t struck a ball over 100 mph at a launch angle greater than 10 degrees once. To be fair, his last two hits on June 8 were both healthy cuts from 98-100 mph at 12-19 degrees (one went for a double, the other an out), but the overall trend lately has been troubling and don’t point to sustained pop.

Jonathan Lucroy - (C/1B, TEX):

Lucroy’s overall average exit velocity has dipped by roughly two ticks since 2016 -- currently 85.9 mph -- and the rate at which he’s delivering barrels per batted-ball event has dropped by more than half, from 7.6 percent to 3.3 percent. That’s bad. Really bad. He hasn’t topped 360 feet on a batted-ball since a 410-foot double off of Heath Hembree on May 23. Yeah, it’s been a while since he’s really gotten a hold of one.

In fact, he’s dropped his already abysmal power metrics to new low over the past two weeks. A 17.1 percent fly-ball rate is fine as long as you’re hitting the ball really hard, but he’s not (11.4 percent hard-hit rate). And he’s hitting the ball the other way much more (40 percent) than he’s pulling it (28.6 percent), marking this as a clear downturn for the already downtrodden.

Catcher is a wasteland this season so it’s hard to say “cut bait” with a guy who we know has a top-three ceiling, but holding out hope may be an exercise in futility here. He’s lost. Like, “went on a hike and left jellybeans behind him to mark his way back but then a flock of sugar-happy bears came by and ate them all so now he’s stuck with no clue as to where to even begin” lost.

Eugenio Suarez - (3B, CIN):

Suarez has been having a fantastic season, sporting a .302/.378/.566 slash line with 10 homers, 30 RBI and two steals over his first 180 plate appearances through May 23. His .217/.333/.304 triple slash since then shows quite a few things, though. The good is that he’s still drawing plenty of walks, but the bad is that one’s slugging percentage should ideally never trail the OBP. He’s swatted just three extra-base hits in those 54 plate appearances -- two doubles, one triple -- thanks to a paltry 18.2 percent-hard hit rate.

The flies are still coming in at 30.3 percent, which isn’t great but it won’t totally zap a guy’s power either, and he’s still pulling the ball the majority of the time at a 39.4 percent clip. It’s just that he can’t square up a ball with any consistency right now. That HH rate was doubled at 36.1 percent prior to this cold stretch! I believe he’s been good enough where you could still “hold” and not feel guilty, but selling on his still-respectable full-season line thus far isn’t the worst move either.

More Risers and Fallers

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