7 Must-Add Waiver Wire Pickups for Week 18 Fantasy Baseball (2026)

July 25, 2026

Kevin breaks down his must-add fantasy baseball waiver wire pickups for Week 18 of the 2026 MLB season. Add these players now off the waiver wire and win more.

Hello RotoBallers! Welcome back to another edition of our 7 Must-Adds ahead of Week 18 of the fantasy baseball season. I'm filling in for Andy Smith this week, and I'm hopeful to bring you the same level of analysis he does on a weekly basis here.

This week, we will spotlight seven players who are available in more than 75% of all Yahoo leagues and explain why managers should prioritize them on the waiver wire. Be sure to follow RotoBaller MLB on X for all of our league-winning content and me, @_Kevlar23_, for any questions.

Additionally, be sure to use discount code KEVLAR for 50% off any Premium Packages and gain access to our Team Sync platform with customized lineup tools, projections, and more based on your league settings. Let's dive in!

2026 Fantasy Baseball Week 17 Waiver Wire Adds

Nolan Arenado, 3B, Arizona Diamondbacks

24% rostered

Let's start in Arizona, where the 35-year-old is having a stellar July. He's posted a nice, easy 157 wRC+ that feels like it's going relatively unnoticed. That's all being driven by a .968 OPS with 12 runs, 14 RBI, and five homers. Arenado should surpass each of these marks by the end of the month.

Nolan Arenado is the 297th member of the 2,000-hit club. pic.twitter.com/OeJNNucCKi

— Arizona Diamondbacks (@Dbacks) July 21, 2026

That 14 RBI mark leads the DBacks in July, making him a really solid producer. Coming into Friday night's action, he's had at least one RBI in five of his last six games. Three of those games featured a two-RBI performance, giving the feel of his old days at Coors Field.

Perhaps he hasn't been rostered as highly thanks to a porous June. But take that away, and you have two straight months of a 130 wRC+ or higher. He's looking like a really competitive hitter again.

While there are certainly some indicators that maybe he's had some luck along the way, I'm usually a fan of riding the hot streak until it cools off. With the upcoming week, he won't be seeing any upper-echelon arms, giving him a chance to keep this streak rolling.

Kyle Karros, 3B, Colorado Rockies

20% rostered

From the former Rockies' third baseman to a younger slugger that's looking to become the mainstay at Coors that Arenado was for so long. Karros has been turning it on the past couple of months, posting a 165 wRC+ in the month of June and a 140 wRC+ in July.

471 FEET KYLE KARROS YOU BEAUTY pic.twitter.com/vBmAjTZnE5

— Colorado Rockies (@Rockies) July 5, 2026

He's been a huge reason why the Rockies have been a tougher team to face in July. Not only is he swinging it effectively, but he's been finding other ways on base as he's got a 13.9% walk rate this month. Colorado's offense is taking advantage of him being on base as he's crossed the plate 11 times in July, tied for third-best on the team.

Going forward, he will continue to get opportunities as well. With the Rockies rebuilding and likely to sell at the deadline, there aren't many roadblocks in his way to continue developing. That may hurt a little more in future months when he has fewer people on base for him to drive in, but in the meantime he's a fantastic option to get onto your roster.

Next week, Colorado plays host to the Royals after a two-game set in San Diego. Neither of those teams has been formidable on the mound as of late, making Karros a solid player to target.

Trevor Larnach, OF, Minnesota Twins

8% rostered

This one's a bit surprising for me. Maybe it's because the OF position is relatively deep, but Larnach hasn't been slacking at all. He's posted a 138 wRC+ on the season that's up to 181 in July. And that's not good enough to be on rosters for 92% of the fantasy managers out there?

Trevor Larnach leads off the game with a homer 💪 pic.twitter.com/PCDwoZZo7a

— MLB (@MLB) July 22, 2026

He's getting to those marks thanks to a .340 average in July that's produced 11 RBI. He's not exactly getting lucky either. While his .433 wOBA in July is paired with a .391 xwOBA, which would project negative regression, that's still a .391 xwOBA. He's absolutely crushing it.

So all the trends are going up. If there's a downfall to Larnach's game these past couple of months, it'd be that he simply doesn't hit lefties well. But that's fine as he's mainly a platoon matchup against righties anyway. With him being a left-handed hitter, he's on the right side of the plate for more platoon opportunities.

Find a way to get Larnach in your lineup. Even if you're worried about the Twins' offense falling off, giving him fewer opportunities for runs and RBI, Larnach could be moved at the deadline to a competitor. That simply means more opportunities for him in an assumed strong offense. He's a low-risk add at 8% rostered.

Ty France, 1B, San Diego Padres

22% rostered

Flying under the radar here is the 32-year-old vet who has been San Diego's most productive bat this season (when considering everyday starters). His season-long 139 wRC+ is already impressive enough, but in July it's at a 166 mark. He's straight up cooking right now.

Ty France brings the @Padres back within a run in the 8th! pic.twitter.com/Qm8r6U3NLl

— MLB (@MLB) July 23, 2026

Driving these marks are really solid hard-hit and barrel rates. His hard-hit rate of 50.0% ranks in the 89th percentile and his barrel rate of 12.6% ranks in the 83rd percentile. Both of those would be career highs.

The last time France hit this well in a season, ironically enough, was 2020 on the Padres before they traded him to the Mariners midseason. So we're looking at a bit of a renaissance here. His 14 RBI in the month is tied for the team lead with Fernando Tatis Jr. He's also blasted six homers, a mark we don't normally see from a guy who's been more of a contact hitter throughout his career.

That makes him a really attractive target to aim for on the waiver wire, especially with San Diego's offense heating up. The Padres play host to the Rockies and Giants next week. With neither being dominant on the mound, France has a chance to make a real impact both for the Padres and for fantasy managers alike. He's certainly worth an add in your league.

Zac Thornton, SP, New York Mets

24% rostered

Now let's focus on the pitching. Thornton is the Mets' No. 12 prospect but has been making a really solid impact in the opportunities he's gotten throughout the year. He's posted a 1.93 ERA in four starts and has limited hitters to just a 37.5% hard-hit rate.

Zac Thornton stretched his scoreless streak to 18 frames en route to his first MLB win.

The #Mets' 2023 fifth-rounder sports a 1.93 ERA over his first four big league starts: https://t.co/xymuIbtZ7A pic.twitter.com/nBCsI3XwhC

— MLB Pipeline (@MLBPipeline) July 22, 2026

That hard-hit rate has helped to overcome some of the other metrics of his that don't read as pretty, but either way he's been a solid addition to the Mets' rotation.

What makes him beneficial to add, though, is the fact that New York is going to be selling at the deadline. With Freddy Peralta likely to be dealt, along with Clay Holmes, that should keep at least one rotation spot open for Thornton to continue to pitch.

So while there are certainly some worries with the underlying metrics, that will be balanced out by the additional opportunities he's going to get for fantasy managers. If he's able to perform anywhere close to what he did in the minors in 2025 (1.98 ERA, 2.96 xFIP, 28.5% strikeout rate) then he'll be a very solid addition to your roster. Best to get at it now as he's worth the shot.

Tyler Wells, RP, Baltimore Orioles

18% rostered

Now onto a more well-known name with maybe fewer question marks. Wells has been really solid out of Baltimore's bullpen this season, posting up a 2.94 ERA on the season to go along with a 26.3% strikeout rate. He's been one of Baltimore's best relievers this season.

Tyler Wells has a 26.3 K-BB% (40! K% vs RHH) since June after getting hit hard through May, especially on breakers. His whiff% since then are ridiculous considering the stuff is "bad."
It is, though, pinpoint cmd from the highest release point of any reliever. He's the closer. pic.twitter.com/iIQpylMitx

— marsh🔻 (@thebabygiraffe3) July 23, 2026

His return has been great to see for Orioles fans. After an elbow injury forced him to have Tommy John surgery, he returned late last year in the rotation and has made all of his appearances in 2026 out of the bullpen. He's leading the Orioles in holds and has gotten the occasional save opportunity from time to time.

One area that Wells has improved at, which is significantly helping him this season, is simply getting less contact. His contact rate has dropped from 79.6% last season to 70.9% this season. When hitters are chasing, that contact rate has dropped from 63.5% to 51.6%. Cue the jump in strikeout rate that's helping you from a fantasy perspective.

With Baltimore fighting for the last AL wild card spot, they're sure to be turning to their plus-side relievers more often than not. That should give Wells plenty of opportunities down the line to make an impact for the O's. All three of his saves have come in July as well so there's a chance he moves into the closer role on a more permanent basis.

Brent Headrick, RP, New York Yankees

9% rostered

Let's end this column with another reliever that should absolutely be on your radar. Headrick has been one of the Yankees' best relievers over the past couple of months, posting a 0.69 ERA in June and a 0.79 ERA in July. He's been really solid from a strikeout perspective, racking up a 30.0% strikeout rate on the season.

Brent Headrick has not allowed a run in 41 of his 49 relief appearances, the most in the Majors 🔒 pic.twitter.com/s64O1io76z

— New York Yankees (@Yankees) July 20, 2026

Even more impressively than that, though, is what he's done in July. He's struck out 20 of the 41 batters he's faced for nearly a 50% strikeout rate. You expect a higher rate out of bullpen arms, but that's just off the charts.

Baseball Savant backs him up as a really solid option as well. His 2.74 xERA ranks in the 93rd percentile. His whiff rate and strikeout rate are in the 95th and 94th percentiles, respectively.

The only thing that could make him a more attractive option to pick up would be if he had more save opportunities. But he's one of the Yankees' best bullpen arms and is very much worth a spot on your roster thanks to his ability to rack up the strikeouts.

Other Waiver Wire Targets

• Josh Bell, MIN
• Tommy White, ATH
• Garrett Mitchell, MIL
• Heriberto Hernandez, MIA
• Brandon Sproat, MIL
• Grant Taylor CHW
• Mason Montgomery, PIT
• J.T. Realmuto, PHI
• Lane Thomas, KCR
• Cole Carrigg, COL
• Brandon Pfaadt, ARI

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