The Washington Nationals haven't shied away from calling on their top prospects this season, and that trend continued this week with the promotions of hard-throwing right-handers Reynaldo Lopez and Koda Glover.
Making his big league debut on Tuesday, Lopez, the Nationals' No. 5 prospect, was tagged by the Dodgers for six earned runs on 10 hits in 4 2/3 innings. However, the 22-year-old was mighty impressive as he used his upper-90s fastball and devastating breakingball to accrue 13 swinging strikes and nine strikeouts in the outing. Though Lopez was optioned back to Triple-A Syracuse the following day, his high-octane throws will have him back with the Nats later this season.
Glover, meanwhile, was called up to replace Lopez on the active roster, marking his fourth promotion of the season. The Nationals' No. 19 prospect made an immediate impact in his big league debut on Wednesday, needing just four pitches to record a 1-2-3 ninth inning in a win against the Dodgers.
Selected in the eighth round of the 2015 Draft, Glover, 23, began his first full professional season with Class A Advanced Potomac, where he made seven scoreless appearances to earn a promotion to Double-A Harrisburg. He was bumped up to Triple-A on June 20, and he joined the Nationals' bullpen exactly one month later.
Who might be next to get the call and make a fantasy impact? That's what this weekly feature is all about. Here is a Top 10 list of fantasy prospects currently in the Minor Leagues, ranked based on potential impact this season. Talent is obviously a big factor, but opportunity also figures heavily into the decision-making process. In parentheses is where each prospect was ranked in our previous fantasy ranking.
1. Alex Bregman, SS/3B, Astros (Previous rank: 1)
Bregman has been a one-man wrecking crew since being promoted to Triple-A Fresno, hitting .371 with six homers and six doubles, as well as eight multiple hit performances in his first 16 games. He made his first start in left field on Wednesday, and he has also seen time at third base, which suggests the Astros could deploy Bregman at numerous positions when he arrives.

2. Tyler Glasnow, RHP, Pirates (Previous rank: NR)
Glasnow took the loss in his big league debut on July 7, but the 6-foot-8-inch right-hander was plenty good as he allowed just three hits in 5 1/3 innings. He's back in Triple-A for now, where he has pitched to a 1.94 ERA with a Minor League-leading 122 strikeouts over 18 starts. Glasnow is in line for another big league audition should the Pirates end up dealing a starter before the Aug. 1 non-waiver Trade Deadline.
3. Hunter Renfroe, OF, Padres (Previous rank: 3)
Renfroe has already connected on a Pacific Coast League-leading and career-best 24 home runs this season for Triple-A El Paso, and he also ranks among the top three in hitting, slugging, OPS, runs scored and RBIs. Both Matt Kemp and Melvin Upton Jr. are having fine seasons for the Padres, but it's seemingly a matter of time until the club offers Renfroe a crack at the big leagues.
4. Joey Gallo, 3B/OF, Rangers (Previous rank: NR)
After Wednesday's news that both Shin-Soo Choo and Prince Fielder were headed to the disabled list, and that Fielder could require season-ending surgery, it might not be long until Gallo finds himself back in the big leagues. The 22-year-old hasn't fared well at the plate recently, but overall, he has made enough strides with his plate discipline and approach to warrant a callup.
5. Lucas Giolito, RHP, Nationals (Previous rank: NR)
Giolito was sharp in his Triple-A debut on Tuesday, allowing one unearned run while striking out seven in 6 2/3 innings against Gwinnett. The 22-year-old righty was optioned to the Minors after his two-start big league debut, but there's little doubt that he'll be back with the Nationals when the need arises.

6. Alex Reyes, RHP, Cardinals (Previous rank: 2)
The big arm and power Reyes showcased in his SiriusXM All-Star Futures Game start could make him a weapon for the Cardinals down the stretch. Though he has been hit around lately in his starts, the 21-year-old right-hander is averaging 13.0 strikeouts per nine innings for Triple-A Memphis, and that bat-missing potential could make him a force out of the Cards' bullpen down the stretch.
7. José Berríos, RHP, Twins (Previous rank: NR)
Berrios was underwhelming during his first stint in the big leagues, but he has since gotten back on track at Triple-A Rochester. Over his past six turns, the right-hander has pitched to a 1.08 ERA while striking out 43 hitters in 41 2/3 innings. If Berrios can continue down that path, it shouldn't be long until he rejoins the Twins' rotation.
8. Josh Bell, 1B, Pirates (Previous rank: NR)
Bell's first two at-bats in the big leagues played out like a dream as he hit a pinch-hit single off Jake Arrieta and then blasted a pinch-hit grand slam the following night. He was optioned back to Triple-A following the All-Star break, and he will continue to refine his defense at first base ahead of a permanent callup.

9. Andrew Benintendi, OF, Red Sox (Previous rank: 7)
Promoted to Double-A after just 34 games, Benintendi hasn't skipped a beat in the Eastern League, showing more consistent power while hitting for average and reaching base at a high clip. He might be a bit of a long shot to receive a late-season promotion, and he doesn't have a spot waiting for him in Boston's outfield, but there's little doubt that the 2015 first-rounder would be able to hold his own at the highest level.
10.Joe Musgrove, RHP, Astros (Previous rank: NR)
Musgrove, 23, piled up a season-high nine strikeouts over seven scoreless frames in his most recent start for Triple-A Fresno, giving him a 2.76 ERA and an elite 80-9 strikeout-to-walk ratio through 78 1/3 innings this season between the Double- and Triple-A levels.
All statistics are accurate through the completion of Thursday's games.