These 10 prospects will make an impact soon

Two of the four best prospects in the Minor Leagues got their first call to the Majors in the past week, with the Yankees summoning infielder Gleyber Torres on Sunday and the Braves promoting Ronald Acuna Jr. on Wednesday. What can we expect from them in terms of fantasy production?
Torres has started five straight games at second base, all Yankees wins, and looks very comfortable at the plate, with six hits in 19 at-bats. That's no surprise, because his hitting ability is his strongest attribute. If Torres gets 450 at-bats -- not necessarily a given considering New York's array of infield options -- he could hit 10-12 homers with a handful of steals while posting an average around .275.
Acuna has the best power/speed combination of anyone on MLB Pipeline's Top 100 Prospects list, and he homered among his three hits in his second big league game on Thursday. Assuming he plays regularly the rest of the way and accrues 550 at-bats, a .260 average with 20 homers and 25 steals is a reasonable expectation.

As for the players who are presently in the Minor Leagues, below is our updated rankings of the top 10 for fantasy purposes. As always, these evaluations are based solely on expected 2018 fantasy production in the big leagues, while our Top 100 reflects long-term value in all phases of the game.
1. Nick Senzel, 3B, Reds (Previous rank: 4)
Eugenio Suárez has returned from a thumb injury and Senzel is off to a slow start in Triple-A, but the worst team in baseball should give its lineup a boost by finding a way to play both at the same time. Senzel can rake and has all-around tools, and he's adding second base (and perhaps shortstop) to his resume this year.
2. Willie Calhoun, OF, Rangers (Previous rank: 2)
Calhoun's callup last September means the Rangers have to keep him in the Minors until May to delay his free agency an extra year. His lackluster numbers in Triple-A have made that decision easier, but he still offers an enticing combination of power and contact while Texas' left fielders have struggled.
3. Austin Hays, OF, Orioles (Previous rank: 6)
Hays faces the same service-time situation as Calhoun and was slowed by a shoulder injury in Spring Training. The first player from the 2016 Draft to reach the Majors (despite being a third-round pick), he's starting to heat up in Double-A and would be a huge upgrade in right field for a club with MLB's third-worst record.
4. Michael Kopech, RHP, White Sox (Previous rank: 10)
Kopech arguably has the best pure stuff in the Minors and is throwing more strikes than ever, with a walk rate of 3.0 per nine innings (in a small sample size of four starts) after coming into 2018 with a career mark of 4.5. The White Sox feature just one starter with a sub-6.00 ERA, and the rebuilding club should pull the plug on James Shields and hand his spot to Kopech.
5. Jack Flaherty, RHP, Cardinals (Previous rank: unranked)
Flaherty struck out nine Brewers in five innings on April 3, breezed through three Triple-A starts afterward and will be back in St. Louis on Saturday to fill in for Adam Wainwright, who has elbow inflammation. With solid stuff, even better control and a good team behind him, he could make a significant impact if he gets regular starts.

6. Walker Buehler, RHP, Dodgers (Previous rank: unranked)
Like Flaherty, Buehler has made one nice big league start (five scoreless innings against the Marlins on Monday) and is expected to return Saturday for another as part of a doubleheader. The Dodgers don't have a clear opening in their rotation, but they do have several starters with questionable health histories, and Buehler's stuff is in the same class as Kopech's.
7. Francisco Mejía, C, Indians (Previous rank: 8)
In their quest to find a way to get Mejia into their lineup, the Indians have him alternating between catcher and left field in Triple-A. His defense behind the plate isn't good enough yet to displace the Yan Gomes and Roberto Pérez tandem in Cleveland, but his potent bat could do some damage while he shuttles between the aforementioned positions and DH.
8. Willy Adames, SS, Rays (Previous rank: unranked)
Adames is a better hitter than Rays shortstop Adeiny Hechavarría and no slouch with the glove, and he's superior offensively and defensively to second baseman Joey Wendle. He's also batting .355/.455/.581 in Triple-A after playing well there last year. Adames' time with Tampa Bay could be nearing.
9. Eloy Jiménez, OF, White Sox (Previous rank: 9)
Despite a two-homer game Sunday, Jimenez has gone just 4-for-29 in Double-A after the beginning of his season was delayed by a strained pectoral muscle. He and Blue Jays third baseman Vladimir Guerrero Jr. are still the two best hitters for average and power in the Minors, and the White Sox desperately need some outfield help.

10. Dustin Fowler, OF, Athletics (Previous rank: 7)
The Athletics have already used six players in center field, and none of them can match the 20-20 potential and defensive prowess of Fowler. His five steals in 18 Triple-A games show that he's fully healthy after rupturing the patellar tendon in his right knee in his first big league game last July.
Dropped out: Acuna, OF, Braves (Previous rank: 1); Torres, INF, Yankees (Previous rank: 3); Victor Robles, OF, Nationals (Previous rank: 5).