Must-Add Waiver Wire Pickups: Mid-Week Fantasy Baseball Adds for Week 21

August 19, 2026

Frank analyzes six must-add fantasy baseball waiver wire pickups, mid-week adds for Week 21 of the 2026 MLB season. Grab these players ASAP off the waiver wire.

Hello, RotoBallers, and welcome to the latest installment of the mid-week Must-Add Waiver Wire Pickups for fantasy baseball. At this point of the season, we are past the trade deadline in most fantasy leagues. That means finding fresh talent on the wire to give your team a boost is even more important.

This week is highlighted by three must-add closers, followed by a pair of prospects who are showing potential, with one of them set for a favorable weekend series. There's also a hitting prospect who had gotten off to a slow start, but seems to be finding his groove right now. We've focused on hitters and closers for this week's column, but there are some starting pitcher suggestions at the bottom of the page.

Hopefully this list primes you for success this weekend and in the weeks ahead. If you need more help, ping me in the RotoBaller Discord or tag me on X (@FAmmiranteTFJ). Don’t forget about the host of resources in RotoBaller’s MLB hub, too. For now, get started with my Must-Add Waiver Wire Pickups for Week 21 of fantasy baseball.

2026 Fantasy Baseball: Mid-Week Waiver Wire Adds

Tanner Scott, RP, Los Angeles Dodgers
48% Rostered

Tanner Scott is putting up a 2.32 ERA and a 0.93 WHIP with a 32.0% strikeout rate and a 5.7% walk rate in 50.1 innings. He performed well as the Dodgers' closer in Edwin Diaz's absence, converting 17-of-19 saves. When Diaz returned, there was a reasonable chance that Scott was jettisoned to the waiver wire in your league.

Diaz struggled mightily once he got back to action. Now, he's been placed on the injured list with neck inflammation. Given that Diaz has been highly ineffective since returning, it's unlikely that he'll regain the closer role for the rest of the year. That means that by picking up Scott, you'll have a closer with elite ratios, pitching for the best team in baseball.

The news that Diaz was placed on the injured list came on Tuesday, so that's why we have to make Scott the focal point of this week's column. He can make a major impact for your fantasy team down the stretch, especially if you're desperate for saves.

We saw Scott have a rough outing at Coors on Tuesday, but he still got the save in that one. Expect to see a bunch more with the Dodgers consistently winning games. Make sure to pick up Scott immediately if he's still out there in your league.

Kodai Senga, SP/RP, New York Mets
27% Rostered

I had some high hopes for Kodai Senga coming into the season. I thought that he could bounce back as an effective starter. But that couldn't have been more wrong. However, we've seen the Mets deploy him in a new role as the closer. Yes, this is a team that is completely out of contention, but that doesn't mean we can't find value here, especially if you're desperate for saves.

So far, the experiment is going quite well. Senga has converted three consecutive saves for the Mets. During this stretch, he's pitched three scoreless innings, allowing one hit with one walk and five strikeouts.

Perhaps this can be a case where we have a former starting pitcher finally finding their groove in a new role. It certainly wouldn't be the first time it's happened.

Even though Senga isn't as appealing of a pickup as Scott, he's still worth a look if you're in dire need of saves.

Abimelec Ortiz, 1B/OF, Washington Nationals
20% Rostered

Abimelec Ortiz was slashing .244/.348/.497 with 18 home runs in 365 plate appearances at Triple-A this season. That resulted in a call-up to the big leagues, where he currently has a .279/.295/.651 slash with five home runs in 44 plate appearances. Ortiz is showing that he can make an impact in the power department.

You have to like the batted ball metrics so far, as Ortiz has an impressive 18.2% barrel rate. The one concern here is that he's more of a platoon bat, as the Nationals aren't putting him in the lineup against left-handers. But against righties, Ortiz has a 173 wRC+ so far. That'll play.

ABI OPPPOOOOOO

14 mlb games, 5 bombs pic.twitter.com/SILbomOtgn

— Washington Nationals (@Nationals) August 16, 2026

What's also worth noting here is that all five of Ortiz's home runs have come in the last eight games, so he's clearly in a nice groove right now. Looking at the schedule, we see the Nationals face three righties for the rest of the week when they go up against the Marlins. That's good news for Ortiz.

If you need a boost in power, it makes sense to give Ortiz a look here. You just never know the upside of these rookie hitters. Just look at what Esmerlyn Valdez did for the Pirates earlier this year.

Fantasy Baseball Deep League Targets: Mid-Week Waiver Wire Adds

Ben Joyce, RP, Los Angeles Angels
16% Rostered

Ben Joyce is an oft-injured flame-thrower who is finally healthy for the Angels. We're seeing why he's always been such an intriguing arm, as he's tossed six scoreless innings with one walk and eight strikeouts so far. The stuff has been absolutely off the charts so far, as highlighted by a 125 Stuff+.

Joyce has converted three consecutive saves for the Angels, so it's clear that they're ready to give him the role. While this is one of the worst teams in baseball, so saves should be hard to come by, we can't ignore the prototypical closer arsenal that we see here with Joyce. There's a good chance that he's going to provide you with elite ratios down the stretch.

What's good about Joyce is that he's much more widely available in leagues right now, so make sure to act quickly and pick him up before you even finish reading this sentence. There's a chance that he'll be more valuable than Senga for the rest of the way.

Angel Genao, 2B/3B/SS, Cleveland Guardians
11% Rostered

Angel Genao was slashing .309/.395/.494 with 10 home runs and nine stolen bases in 309 plate appearances at Triple-A this season. Then, the Guardians called him up, and so far, he has a .324/.405/.459 slash with one homer and one steal in 42 plate appearances. This includes an impressive 9.5% walk rate and a 7.1% strikeout rate.

Angel Genao, the man you are.#GuardsBall pic.twitter.com/VLG6Nfobcc

— Cleveland Guardians (@CleGuardians) August 6, 2026

What I like about picking up Genao right now is that since the numbers don't jump off your screen, he's widely available for you, just in time for a weekend series at Coors Field.

With how much contact Genao is making at the plate, this is the ideal spot for him to break out at the plate.

Braden Montgomery, OF, Chicago White Sox
7% Rostered

Braden Montgomery got off to a slow start in the big leagues, but he's starting to find his groove, hitting safely in four of his last five games. Since his slash is still underwhelming at .233/.325/.367, you can still pick him up, since he's widely available.

You have to like the plate discipline so far, featuring a 10.8% walk rate and a 22.5% strikeout rate. Remember, Montgomery had a 149 wRC+ across all minor-league levels this season. This looks like a polished bat who is finally finding his groove in the big leagues.

Pick up Montgomery in deeper leagues to see if he can get hot.

Other Fantasy Baseball Waiver Wire Targets

• Masyn Winn (SS - STL)
• Andre Pallante (SP - STL)
• Kodai Senga (SP, RP - NYM)
• Daulton Varsho (OF - HOU)
• Dominic Canzone (OF - SEA)
• Walker Buehler (SP - SDP)
• Mason Montgomery (SP, RP - PIT)
• Dean Kremer (SP - MIN)
• Justin Crawford (OF - PHI)
• Javier Sanoja (2B, 3B, SS, OF - MIA)

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