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5. SS Royce Lewis, Minnesota Twins (A+)

The No. 1 pick in the 2017 draft, Lewis hit .292/.352/.451 with 46 extra-base hits and 28 steals in Single-A and High-A in his first full pro season. The Twins took a cautious approach by returning him to High-A, and he's stumbled a bit this year with a .226/.281/.325 line and a strikeout rate that has spiked from 15.7 to 22.3 percent. His age (20) and track record earned him the benefit of the doubt this time, but he'll start to slide in the next update if he doesn't right the ship.

4. LHP MacKenzie Gore, San Diego Padres (A+)

Gore has taken a step forward this season into the conversation regarding baseball's best pitching prospect. With a polished four-pitch mix, strong 6'3", 195-pound frame, and a deceptive delivery, he's been a nightmare for minor league hitters. In 12 starts at High-A Lake Elsinore, he's pitched to a 1.21 ERA and 0.69 WHIP while holding opposing hitters to an absurd .137 batting average and racking up 83 strikeouts in 59.2 innings. The 20-year-old is ready for the next challenge.

3. OF Jo Adell, Los Angeles Angels (AA)

After dealing with ankle and hamstring injuries during spring training, Adell is back to 100 percent and has gotten right to work making up for lost time. The 20-year-old is hitting .328/.400/.582 with eight doubles, three home runs and 12 RBI in 18 games between High-A and Double-A. He's a true five-tool standout and a potential superstar in the making who could join Mike Trout in the Angels outfield by 2020.

2. RHP Casey Mize, Detroit Tigers (AA)

After giving up just seven hits in 26 innings at High-A, Mize earned a quick promotion and threw a no-hitter in his Double-A debut. All told, he posted an 0.92 ERA and 0.69 WHIP with 75 strikeouts in 78 innings before he left his most recent start with minor shoulder inflammation. There's no reason for long-term concern, but the Tigers will be extremely careful. After all, he's an ace in the making.

1. SS Wander Franco, Tampa Bay Rays (A)

With Fernando Tatis Jr. joining Vladimir Guerrero Jr. and Eloy Jimenez in exhausting their rookie eligibility, there's a new No. 1 prospect in baseball. Signed for $3.8 million as part of the 2017 international class, Franco hit .351/.418/.587 with 28 extra-base hits in his pro debut as a 17-year-old in the Appalachian League last year. Aggressively sent to Single-A this season, he's responded with a .326/.396/.514 line that includes 15 doubles, four triples, six home runs and 14 steals. Oh, and he won't turn 19 until March 1, 2020. This is the next teenage phenom, folks.

All stats courtesy of Baseball Reference and FanGraphs, unless otherwise noted.