NL-Only and AL-Only Waiver Wire for Week 20

Matt Wallach outlines his favorite week 20 waiver wire pickups and adds for deep leagues, and AL-only or NL-only fantasy baseball leagues for the 2021 MLB season.

Welcome back to the NL-only and AL-only pickups column. Each week, I'll look at five players who are under 15% rostered in Yahoo! leagues and who can be considered as options to add in deep-league formats, such as 15-teamers or AL or NL-only leagues.

I'll also include a recommendation for what to do with each player on your roster. And lastly, I'll take a look at some of my picks from the previous week to see how they're performing.

Without further ado, let's get into it.

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Sam Hilliard - OF, Rockies

9% rostered
Recommended move: Add for a few weeks 

While his overall .226/.294/.548 slash line isn't particularly impressive, Hilliard has been on fire for the Rockies as of late. He's hit a whopping .435/.480/1.087 since the start of the month as he has been one of the hottest players in baseball for the last week or so. In that span, he's hit four home runs, which matches up well with his power-heavy profile that's been the carrying part of his slash line for the entire season.

Hilliard has had stretches like this where he has played his way into fantasy relevance, most notably in 2019 when he hit .273/.356/.649 in 27 games down the stretch for the Rockies. He wasn't able to follow it up all that well with a poor 2020 showing. He made the team out of spring training but struggled out of the gate and was sent down to Triple-A. Since being recalled in mid-July, he's been much better. He's been crushing the ball with a 41% hard-hit rate, but what's most impressive is his 20.5% barrel rate in that span. Additionally, he's cut down on strikeouts, which have been what has held him back the most in his career. He has a 35.3% strikeout rate for the year, but he's been running a more manageable 27% strikeout rate since his call-up, all while walking more too at a comfortable 11.1% clip.

Of course, what makes this more intriguing for fantasy purposes is that Hilliard will be playing his home games in Colorado. The Rockies are on the road all week, unfortunately, but this still seems like a solid add for this week because of how hot he's been at the plate. He could be benched this week until the team returns home, but right now, he's been hitting too well to be ignored and left on the wire.

Yandy Diaz - 1B/3B, Rays

6% rostered
Recommended move: Add for a few weeks

The playing time situation for Diaz looks to be a bit messy. Out of six games last week, he started four, and not in a way that would suggest he's in a platoon, as he started two games each against both lefties and righties. Rather, it seems like he's just splitting playing time with Ji-Man Choi, and getting the odd start at third base for Joey Wendle. It's harder to roster a part-time player in fantasy, but Diaz has been doing good things at the plate recently that could lead to strong results.

He's been hitting much better lately with a .310/.323/.621 triple slash since July 29, and what is most notable about that is the increase in slugging percentage, and by extension, his isolated power of .310, both of which easily trump his marks for the season of .372 and .119, respectively. He's definitely been hitting for more extra bases lately, with three doubles and two home runs in this stretch. That's important because that has been Diaz's biggest issue as a hitter at the Major League level since his debut. He could hit the ball hard, but he hit too many on the ground. In this hot stretch, he has been hitting the ball hard, with a 48% hard-hit rate, but his average launch angle has been 8.6 degrees, which is higher than his career-best 6.2-degree mark for the season. Meanwhile, his fly-ball rate has spiked to 44%, up big time from the 31.7% mark for the season, which would also be a career-high for him. All told, these are definitely considerable improvements from where he's been previously in his career.

We'll ultimately have to see if Diaz can make this stick for the remainder of the season, but a Diaz that is hitting the ball hard in the air could be a scary thing for opposing pitchers, and would definitely be a good thing for fantasy managers. It would be a lot better with everyday playing time, but he should at least be in the Rays' lineup most days, which might be good enough depending on the circumstances.

Jack Mayfield - 2B/3B/SS, Angels

6% rostered
Recommended move: Add for a few weeks 

Sticking with another hot hitter, Mayfield has been one of the game's hottest hitters since the start of August. He's shown good power with an impressive .321/.345/.714 line with three home runs in that span. He's done well overall since joining the Angels in early July with a 133 wRC+, as he has done a more than solid job replacing Anthony Rendon (hamstring) who will be out for the rest of the season with a hamstring injury.

Mayfield has shown good pop for sure, but he does have a big strikeout issue, which may ultimately limit his upside. His strikeout rate for his career is 27.2%, and that's held up pretty true to his 27.5% rate for this season. Even during this power heavy stretch, he still has run an elevated 31% strikeout rate, which is definitely not ideal. As he comes down from this hot run of form, expect the batting average to drop a good amount. Mayfield still does have a good profile for a power hitter though, as he does have a high 48.7% flyball rate, so at the very least, he should be a good source for some cheap power for the final part of the season, while perhaps not contributing all that much else. He should have a lock on the third base job for the Angels for the rest of the season too, so playing time shouldn't be an issue. He's worthy of a look for fantasy purposes just to see if he can run into a few more homers.

Luis Garcia - 2B, Nationals

1% rostered
Recommended move: Add for a few weeks 

Garcia pretty much has the everyday second base job for the Nationals for the remainder of the season, which makes him a lot more fantasy relevant. His overall .200/.250/.417 line isn't impressive, but he has shown modest power with a .217 ISO and three home runs in just 64 plate appearances. He's been hot in his last five games too with a .316/.350/.737 line, which perhaps shows that he's getting more comfortable at the plate and facing Major League pitchers.

His prospect reports show he has a strong hit tool, so he could be a good fantasy option for fantasy purposes for the rest of the year. For that to happen though, he'll have to get some better luck in terms of his BABIP, which is sitting at just .200 for the season, as that will be key for him since he's definitely not going to keep hitting for this much power in the long run. Notably, his BABIP was .308 during his excellent last five games. We'll have to see what he can do for the remainder of the year, as this profile is far from certain, but he has everyday playing time in hand and can perhaps be a good accumulator down the home stretch.

Hoy Park - SS, Pirates

1% rostered
Recommended move: Add for a few weeks 

Another player with seemingly solid playing time for the remainder of the year, Park impressed with a strong minor league slash in the Yankees system before being moved prior to the deadline to the Pirates. With the team not having much to play for this year, Park has slid into not only the starting shortstop role but also as their leadoff hitter, which means he could accumulate quite a bit of fantasy value.

He's done well since making his debut with the Pirates too, with a solid .320/.370/.480 line in his first seven games with the team. That line probably won't be sustainable, and it's still a small sample and the Statcast metrics still leave something to be desired so far, but Park looks like he could be a decent all-around option for fantasy. Not hurting in any one particular category, but at the same time, not having one standout category. He could soon gain multi-eligibility, which would be another plus, as he has already made three starts in the outfield for the Pirates. Additionally, Park has a history of stealing bases in the minors, as he eclipsed double-digit steal totals in each minor league season going back to his 2015 debut, including a 20 steal season back in 2019, so there could some stolen base upside in this profile too.

Reviewing Last Week's Picks

At the end of each week's post, I'll review what happened with last week's picks and offer a suggestion for them in the future.

Tyrone Taylor (OF, MIL)  

Last week: 9% rostered. This week: 4% rostered. 

Taylor was recommended just for last week, as that was expected to be the final week of everyday playing time before Christian Yelich came back off the COVID IL. Taylor also didn't help himself all that much with a poor showing last week, as he had just two hits. Even if he performed well, it was likely to be a drop just due to playing time issues, but the poor performance makes the decision easier.

Current recommendation: Drop. 

Gregory Polanco (OF, PIT) 

Last week: 5% rostered. This week: 4% rostered. 

Polanco had been doing good things again at the plate since the start of July, but the good results sort of dried up last week as he had just a 43 wRC+. The differences in his profile still look encouraging, and he'll have all of the playing time for the Pirates in right field for the rest of the season, so one bad week shouldn't get him off the radar completely. Give him at least one more week.

Current recommendation: Hold. 

Ji-Man Choi (1B, TBR) 

Last week: 4% rostered. This week: 3% rostered. 

Choi is starting to flounder at the plate, as he went hitless last week. It was mentioned during Diaz's recommendation this week that Choi is starting to lose playing time, and while he should be in the lineup most of the time, if he's not hitting, he'll have little value. The Rays have some more favorable matchups this week against the Red Sox, Twins, and then Orioles after that, so there could be good results coming for him. It depends on the situation, but I would give Choi another week as well.

Current recommendation: Hold.  

Carter Kieboom (3B/SS, WAS) 

Last week: 2% rostered. This week: 9% rostered. 

Kieboom may finally be starting to live up to his top-prospect potential, as he had another standout week, hitting for a 152 wRC+ with two home runs. Playing time is his and he's hitting well, and you're happy and holding.

Current recommendation: Hold. 

Brent Rooker (OF, MIN) 

Last week: 1% rostered. This week: 1% rostered. 

Rooker looked to have made strides in terms of strikeouts going into last week, but he struck out 34.4% of the time last week, and had just three hits as he looks to be coming down from his hot stretch. The power potential is intriguing and he could easily heat up and become relevant again, but there are better outfield options available right now.

Current recommendation: Drop. 

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