Need an impact arm or bat that can give your fantasy team a boost? Whether you're looking for an injury replacement or someone to stash on your bench, the fantasy waiver wire has a plug or long-term fix to pick up today. Check out the following 10 players -- all sitting on waivers in many leagues, and all ready to help your team in Yahoo Sports Fantasy Baseball, the Official Commissioner Game of MLB. All statistics and ownership percentages are as of Wednesday.
Player Page for David Robertson, reliever, Yankees (50% owned)
While the Yankees have given save chances to Robertson, Zach Britton and Dellin Betances in Albertin Chapman's injury-related absence, Robertson has had the most success of the trio. Since Aug. 17, Robertson has converted three saves -- as many as Betances and Britton combined. He also hasn't blown any opportunities, whereas Britton and Betances have each failed to convert one. Robertson has been lights-out since the beginning of August, allowing no earned runs while ringing up 18 strikeouts in 12 2/3 innings over his past 12 appearances. With Chapman still potentially a few weeks away from returning, Robertson should remain in the mix for saves and see a short-term boost in value as a result.
Miguel Sano, third baseman, Twins (47% owned)
After spending much of the summer in the Minor Leagues ironing out his swing, Sano has been a good source of power since returning to the Twins on July 28. In his first 34 games back, he's tallied six home runs and 14 RBIs while showing a solid batting eye (12.9 percent walk rate) as Minnesota's regular cleanup hitter. He's still striking out too much (34.1 percent K rate), but the 25-year-old's raw power and middle-of-the-order presence make him worth adding in deeper leagues.

Corey Knebel, reliever, Brewers (43% owned)
Following a poor August in which he lost the closer's job and was demoted to the Minor Leagues, Knebel has looked like his old self since returning to the Brewers last weekend. He's yet to allow a baserunner in three appearances while recording five strikeouts in 2 1/3 innings. If he keeps it up, the 2017 All-Star may be able to reclaim closing duties by season's end.
Ryon Healy, first baseman/third baseman, Mariners (29% owned)
Healy's poor plate discipline (career four percent walk rate) and high whiff rate (22.1 percent) make him a streaky hitter, but he's been blazing hot lately, slashing .354/.391/.523 with three homers and 13 RBIs over his past 18 games. Fantasy owners should look to capitalize and get him in their lineups while he's swinging the bat well.

Hector Neris, reliever, Phillies (29% owned)
Neris lost his closing job and was sent down to Triple-A following a poor first half, but he's been a completely different pitcher since returning to the Phillies in mid-August. He hasn't allowed an earned run in his past 11 appearances while posting an eye-popping 21-to-2 K/BB ratio in just 9 2/3 innings. With batters hitting just .147/.194/.176 against the righty since his return, it wouldn't be a surprise if he gets another crack at closing in the near future.
Joey Lucchesi, starter, Padres (28% owned)
Lucchesi hasn't generated much buzz this season, but the 25-year-old has been one of the most consistently effective rookie hurlers, recording a 3.59 ERA with a 1.26 WHIP and a 4.00 FIP in 22 starts. And while he's averaging just five innings per start, it's not a result of poor command (3.2 K/BB ratio). The left-hander can help in most leagues down the stretch.

Franmil Reyes, outfielder, Padres (26% owned)
Reyes has been one of baseball's hottest hitters since the beginning of August, slashing .316/.372/.696 with nine home runs and 15 RBIs over his past 28 games. He's been even better in the past two weeks, crushing six homers and hitting safely in 13 of his past 14 games. The key for him has been cutting down on his whiffs, as he's improved from a 37.8 percent strikeout rate through the end of July to a 23.2 percent strikeout rate since. The 23-year-old rookie's power is immense, and now that he's making more consistent contact, he's becoming a must-own asset in fantasy leagues.
Jose Alvarado, reliever, Rays (25% owned)
Alvarado has quietly been one of the most dominant relievers in baseball over the past three months. Since June 12, he owns a 1.19 ERA and a 1.05 WHIP with 34 strikeouts in 30 1/3 innings, limiting opponents to a .165/.260/.202 batting line over that stretch. He's started seeing more action at the end of games as well, picking up six saves along the way. While his save chances have been inconsistent, the 23-year-old sophomore is still worth owning based on his strong rate stats and strikeout totals.

Welington Castillo, catcher, White Sox (17% owned)
While his season was marred by an 80-game suspension, Castillo is back with the White Sox and will be the team's regular catcher through the end of the year. One of baseball's best power-hitting backstops, Castillo was batting .267/.309/.466 with six home runs through 33 games before being suspended in late May. After slugging 20 homers in just 96 games last year, the 31-year-old could be a useful bat for fantasy owners in two-catcher formats or AL-only leagues.
Brandon Lowe, second baseman, Rays (6% owned)
Lowe initially struggled upon reaching the big leagues on Aug. 5, going 0-for-19 before notching his first career hit. He's been on fire ever since, however, batting a sizzling .364/.462/.636 with three homers and 12 RBIs over his last 15 games. The 24-year-old has shown a good batting eye during his hot streak as well, posting a 7-to-10 BB/K ratio. After slashing .281/.374/.465 across three Minor League seasons, Lowe has posted a similar overall batting line (.254/.365/.444) since being called up and could be poised for additional success.