Fantasy Baseball Waiver Wire Adds: Week 21

With the 2021 baseball season in full swing, nailing the waiver wire and the players available are critical to beating out your league-mates in season-long leagues.

Each week we will take a look at players who are rostered in fewer than 50% of Yahoo leagues and can help out your season-long squads. Remember, if you aren’t scouring the waiver wire, you are falling behind.

Lewis Brinson, OF, Miami Marlins

Roster Percentage: 38%

Could we really be seeing the real Lewis Brinson?

The numbers over the last two weeks, quite frankly, read like a misprint. After hitting under the Mendoza Line in his first 800 career plate appearances in the big leagues, the mega prospect is showing signs of life, sporting 17 runs batted in with three home runs in that time. He's hitting .354 in August with four jacks.

The pitching matchups aren't particularly spicy for Brinson this week, but if he's this hot, it may not matter. He's worth scooping up and seeing where this goes.

Drew Smyly, SP, Atlanta Braves

Roster Percentage: 38%

Let's start things off here with a mea culpa -- I was flat wrong on Drew Smyly this past week. I did not expect was six brilliant innings against the juggernaut offense of the Cincinnati Reds in which he fanned seven.

He has another solid matchup on Sunday versus the Washington Nationals, and if he deals again, he'll be a hot commodity. I'd recommended getting him ASAP, because he's got another decent matchup next week versus the Baltimore Orioles.

For the season, the marks aren't special -- a 4.41 ERA, 1.36 WHIP and 92 punchouts in 102 innings -- but he can take advantage of good matchups.

Elieser Hernandez, SP, Miami Marlins

Roster Percentage: 45%

Can we expect this level of absurdity from Elieser Hernandez to finish out the year?

After starting off the season quite impressively before going down with a leg injury while running the bases, Hernandez has been incredible in his rehab starts. In his last outing, the righty posted 10 strikeouts and did it with only 62 pitches. That's somewhat incredible. That follows up a start in which the right-hander struck out five over four scoreless innings in his last rehab start.

Hernandez is a great add for Sunday's start against the Chicago Cubs, and he's worth clinging on to if that one goes well.

Hunter Renfroe, OF, Boston Red Sox

Roster Percentage: 23%

If you need pop in an outfield slot, Hunter Renfroe could be your pick of the week after Lewis Brinson.

We know Renfroe can go through some wild hot streaks, but even this has been crazy for him. In the last 14 days, he has slammed his way to 12 runs, six long balls, and 13 RBI.

Now, Renfroe comes with batting average risk -- during this hot streak, he's still rocking just a .260 average. But if you can stomach that, he's worth considering.

Notable Two-Start Pitchers to Consider This Week

Alec Mills (CHC) -- vs MIL, at MIA
Triston McKenzie (CLE) -- vs OAK, at DET
Carlos Hernandez (KC) -- vs NYY, vs STL

Games in Coors Field This Week

San Diego Padres (3), Arizona Diamondbacks (3)