RotoBaller's Nick Mariano looks at some fantasy baseball bats for week sixteen that are hitting 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 and Aaron Judge are strong or that Jarrod Dyson and Billy Hamilton are toward the bottom in average exit velocity. Let's wade into the second half of the fantasy baseball season, but do note that the "last two weeks" is missing a good chunk of time due to the All-Star break, so most of this will be regarding July as a whole. Please note that this had to be written before the completion of Thursday's night games.

Identifying top power risers and fallers for each week can help you swing the best deals and 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 15 power risers and selling these week 15 power fallers.

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Power Risers

Justin Smoak - (TOR, 1B):

This may seem odd given that he only has two homers in July after cranking out 10 dingers in June, but while his pull rate is holding steady at around 33 percent, his fly-ball rate has crept up six percentage points and his hard-hit rate has jumped from 31.5 percent to 50 percent. Somehow, his HR/FB rate -- which sat at 29.6 percent in May and 29.4 percent in June -- has fallen off to a monthly-low 9.5 percent anyway. The results should come to fruition soon, but it appears his approach at the plate hasn’t actually dropped off.

Okay, that first paragraph is what I had jotted down prior to Toronto's day game against Boston in which Smoak went yard twice. See, fruition! Seriously, this guy's power stroke is legitimate and I don't anticipate it falling off anytime soon. He's always had the muscle, he just needed to get his swing plate, timing and hand positions all synced up. Just sit back and watch him go.

Odubel Herrera - (PHI, OF):

Herrera has enjoyed a 25 percent HR/FB rate in July -- a rate that will surely settle toward his usual 10-12 percent range -- but is notably pulling the hell a lot more this month. His fly-ball and hard-hit rates are basically unchanged -- sitting around 30 and 35 percent, respectively -- but his pull rate has jumped from 24.4 percent to 45 percent thus far. It's all come together to see him already tie his monthly-high in homers (three) alongside four doubles after swatting 13 doubles, one triple and two long balls in June (in double the at-bats). All of his XBH this month have come in his last seven games, actually, as he's really started to resemble a fantasy commodity again. There's the small matter that he's only been successful on 5-of-10 steal attempts this season, with his 25 steals in 2016 responsible for much of his value, but his power stroke is what we're concerned with here.

DJ LeMahieu - (COL, 2B):

LeMahieu, 2016’s National League batting champion, has left the yard just once in each month of the 2017 season thus far, but his average continues to trend upward. He’s gone from hitting .263 in April to .296 in May, then spiking that figure to .343 in June only to see him open July by roping hits at a .378 clip. Despite only turning in three extra-base hits on his 17 hits in the month, the 29-year-old has earned his success by turning a large chunk of his “medium” contact into “hard” contact. His fly-ball rate is up roughly six percentage points (to 25 percent) and his pull rate is still hovering around 20 percent, but his hard-hit rate has shot up from 29.5 percent to 47.7 percent. It hasn’t sat above 30 percent in any month so far and he didn’t top 40 percent in any month last season.

Charlie Blackmon - (COL, OF):

It seems like a distant memory when Blackmon only popped four homers in a 30-game stretch spanning much of June, but now he’s ripped off a 14-game hitting streak that houses six homers -- including three long balls in his last four games. Well, okay then, Chuck. As you might conclude from his inclusion here, his success is no fluke. The star has boosted his fly-ball rate by eight percentage points and still holds his usual 45 percent pull rate, but as with so many others in these summer months, it’s his exit velocities that are propping up his power. His soft-medium-hard profile in June slipped to 25.9 percent-48.2 percent-25.9 percent, and now it sits at 10.4 percent-41.7 percent-47.9 percent. He’s back, y’all.

Power Fallers

Alex Avila - (DET, C/1B):

Avila hasn’t homered since June 28. He has one RBI since then, and even that came all the way back on July 2. After hitting .317 in June, the 30-year-old’s resurgent 2017 campaign has come to a complete halt with a cold .162 average here in July. To his credit, his still has 10 walks against 14 strikeouts (he logged 11 walks in nearly 30 more June plate appearances), but we’re here for power. His hard-hit rate that had sat above 55 percent in each of this season’s first three months has fallen to 34.8 percent, and his fly-ball rate has cut itself down by 20 percentage points to a meager 17.4 percent. Not good.

J.D. Martinez - (ARI, OF):

Worries about his hand aside, I think it’s worth noting that Martinez had seen his pull rate slip by over 10 percentage points in July alongside a 15-percentage-point dip in hard-hit rate. The good news, of course, is that he’s still hitting .327 with four doubles and three homers this month in only 49 at-bats, but hopefully, hitter-friendly Chase Field can resuscitate his metrics under the hood. Personally, I have high hopes for JDM in Arizona, but one only needs to look at his teammate, Jake Lamb, for how a hand injury can come out of nowhere and zap a swing. Of course, there's always another piece of the puzzle where the swirling trade rumors were getting to his head a bit, and now that it's settled then he can rebound. How comfortable you are with gambling on these things is on you, but I've unloaded him in one league already on the promise of Arizona's hitting environment and his early July numbers.

Jonathan Schoop - (BAL, 2B):

Schoop has opened the second half of the season by going 9-for-24 (.375) with three doubles, five runs scored and six RBIs. He had slugged three homers before the All-Star break in July as well and is hitting .333 overall on the month. Most of his rates are holding steady, but it’s worth noting that he’s lost eight percentage point off of his line-drive rate (all siphoned into grounders) with a 20-percentage-point drop in his pull rate. That mark normally sits above 50 percent, and while the all-fields approach tends to work out for batting average, the momentary loss of power is reasonable. We know that he fell off in 2016’s second half, hitting just .225 after turning a .304 mark in the first half, though he still popped off 11 second-half HRs (14 before the Midsummer Classic). Just all things to keep in mind, but hopefully this doesn’t signal a loss in pop.

Brett Gardner - (NYY, OF):

Gardner’s overall 15 homers and 12 steals have been a fantastic help to fantasy owners looking for a power/speed threat, but it seems Brett is channeling his April form suddenly. You know, when he went through the first 17 games of the season without breaking out the home-run trot? Well, his last long ball came on June’s final day, and ever since then, he’s been ravaged by a paltry 13.5 percent hard-hit rate (36.3 percent in June). While he’s still hitting a fly ball on one of every three batted-balls, his pull rate is down to 32.4 percent after sitting above 40 percent from April-June. He may just be prone to the power streaks and hopefully his two-double game on Monday signals a rebound, but the dip in squaring up pitches is rather staggering.

More Risers and Fallers