The waiver wire. Free agent budgets (FAB). It's back, it's real and it's glorious.

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.

Jed Lowrie, 2B, Oakland Athletics

Roster Percentage: 27%

As many New York Mets fans feel, this organization may truly be cursed -- after signing Jed Lowrie to a free agent deal, it didn't go so well in a few injury-marred seasons in New York.

But this season? Dude has been a friggin' boss. Spanning 339 plate appearances, Lowrie has rocked a 118 wRC+, including 11 home runs, a .435 slugging percentage, and just shy of a double-digit walk rate.

Lowrie won't help much in the stolen base department, but he will help in every other category -- and if you need some help and have the speed to burn with other players, peep Lowrie.

Chris Flexen, SP, Seattle Mariners

Roster Percentage: 50%

After bouncing around from the New York Mets to the KBO to the Seattle Mariners, it's okay if fantasy owners are a bit surprised by Chris Flexen. But if you continue to sleep on him, he's not going to be around for too much longer.

So far in 99 1/3 innings pitched, the right-hander has been more than a serviceable option at the back-end of fantasy rotations, logging a 3.35 ERA, 1.20 WHIP, and winning 9 games so far. Now, there's a major warning sign here -- when you add a guy like Flexen, you have to make sure you have high strikeout arms on your staff. He owns only a 16.3% strikeout rate this year.

Joc Pederson, OF, Atlanta Braves

Roster Percentage: 30%

If you are sick of all of the injuries so far this season in baseball, your stomach was doing double back-flips when Ronald Acuna went down awkwardly, and it was as bad as feared -- he tore his ACL and we can only hope that he's back and available for the start of Spring Training next year.

Quickly, the Atlanta Braves moved into position -- and they traded for veteran outfielder Joc Pederson this week. The lefty has been thrust right into the bright lights, batting leadoff in Acuna's absence.

While no one expects him to match Acuna's production, Pederson has been pretty solid, slamming 12 long balls on the year. If your fantasy team can stomach some volatility in batting average (Pederson is currently only hitting .233), he could be a massive pickup down the stretch.

Jarren Duran, OF, Boston Red Sox

Roster Percentage: 51%

Perhaps one of the more notable pedigreed prospects in the game, Jarren Duran of the Boston Red Sox got the call-up, and oh baby is it time to fly.

The dude is a monster, and we are hyped for pretty good reason -- he's got a monster power-speed combo, and so far this season in Triple-A, he notched 15 homers and 12 steals in only 219 plate appearances.

In his major league debut, he occupied a premium spot in the lineup (sixth), and he swiped a bag off of Gerrit Cole. Add him where he's available.

Notable Two-Start Pitchers to Consider This Week

Alec Mills (CHC) -- at STL, vs AZ

Tarik Skubal (DET) -- vs TEX, at KC

Tony Gonsolin (LAD) -- vs SF, vs COL

Games in Coors Field This Week

Seattle Mariners (2)