We constantly move players up and down and in and out of our top 10 fantasy prospects list. Often, a prospect comes off because he's been promoted to the big leagues, and we only consider players currently in the Minor Leagues for this list.
Sometimes players drop off because they aren't performing as well as hoped. And then, sadly, occasionally a player needs to be removed because of injury. Such is the case with Reds infield prospect Nick Senzel.
Senzel, who we were all hoping would get a chance in Cincinnati soon (where his positional flexibility could have been a boon to fantasy owners everywhere), is now out for the season because of a torn tendon in his finger. He'd been a mainstay at or near the top of this list all year, even when he missed some time while dealing with a bout of vertigo. Now we'll have to wait for 2019, when a healthy Senzel should get a shot to make the Reds' Opening Day roster.
Here are our updated rankings of the 10 best fantasy prospects presently in the Minors. As always, they're 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. Kyle Tucker, OF, Astros No. 1/No. 9 overall (Previous rank: 3)
Tucker has been as hot as any player in the upper levels of the Minors, with an active 17-game hitting streak. He's gone 34-for-72 (.472 average) with five homers during the streak, and he's clubbed 13 long balls with 14 steals for the season. Who wouldn't want that in their fantasy lineup? The Astros haven't shied away from calling up guys in the second half who aren't on the 40-man roster (Alex Bregman comes to mind).
2. Eloy Jimenez, OF, White Sox No. 1/No. 3 overall (Previous rank: 1)
Jimenez is finding his footing in Triple-A, with his first two homers at the level coming since Sunday. Combined on the year, he has a gaudy .308/.366/.540 line. Jimenez is already on the 40-man roster, so that isn't an issue, and the move to Charlotte for the 21-year-old is clearly a precursor to an eventual audition in Chicago -- one you won't want to miss.

3. Vladimir Guerrero Jr., 3B, Blue Jays No. 1/No. 2 overall (Previous rank: 2)
Guerrero Jr. is still the best hitting prospect in baseball, but he's one who hasn't played since June 6 because of a knee injury that's not expected to be a long-term concern. When the injury was first announced, an estimate of four weeks was given for his return, and we're starting to get close to that timetable. Look for the Blue Jays to err on the side of caution, which could slow Guerrero Jr.'s progress to Toronto a bit.
4. Michael Kopech, RHP, White Sox No. 2/No. 11 overall (Previous rank: 6)
It continues to be an up-and-down season in Triple-A for the flame-thrower. And every time Kopech has a strong outing, like he did in his most recent start on Monday (6 IP, 4 H, 0 ER, 2 BB, 9 K), there's hope he's going to take off. The big league rotation is still in need of improvement, and it's up to him to find some level of consistency so his strikeout ability can be seen in Chicago.

5. Forrest Whitley, RHP, Astros No. 2/No. 10 overall (Previous rank: 5)
Yes, the Astros discussed bringing Whitley up last year to help in the stretch run. But he did start this season with a 50-game suspension, and the righty has just 16 1/3 innings under his belt so far this year. Whitley has yet to get through five innings as he stretches himself out, so patience will be key. Outside of his last clunker of an outing, his stuff is just as good as ever, so keep an eye on his usage, as he could bring strikeouts and a low WHIP to your fantasy team if/when he gets the call.
6. Justus Sheffield, LHP, Yankees No. 2/No. 41 overall (Previous rank: 7)
While it was interesting that the Yankees called on Jonathan Loaisiga to help out the big league rotation instead of Sheffield, that might have had more to do with Loaisiga already being on the 40-man roster while Sheffield isn't. Still, more assistance could be needed, especially if the Yanks don't trade for a veteran starter.

7. Fernando Tatis Jr., SS, Padres (Previous rank: 8)
The teenaged shortstop has completely shaken off a terrible start to his 2018 season, posting a 1.054 OPS in May and putting up a .298/.379/.440 line in June. TTatis Jr. is once again is showing the kind of power-speed combination (12 homers and 12 steals) that should excite any fantasy owner.
8. Keston Hiura, 2B, Brewers No. 1/No. 31 overall (Previous rank: 9)
Hiura has spent just 23 games in Double-A, but he's quickly showing his bat is ready for another challenge. He had a seven-game hitting streak snapped Thursday, and he has hit .341/.396/.534 since his move up to Biloxi. Hiura has hit nine homers and swiped 10 bags combined for the season, and he could help the Brewers stay atop the National League Central, with current second baseman Jonathan Villar having just a so-so season in Milwaukee.
9. Willie Calhoun, OF, Rangers (Previous rank: 10)
I'm about ready to start a "Free Willie" campaign, though truthfully the left fielder hasn't completely set the world on fire. That said, after a rough April, Calhoun has done what he's always done: hit. The power hasn't shown up completely, but he did bat .303/.327/.413 in May and is slugging .455 so far in June.
10. Peter Alonso, 1B, Mets (Previous rank: Unranked)
The Mets have used Wilmer Flores a lot at first, and he's been OK. Dominic Smith has been playing the outfield. Meanwhile, Alonso has slugged his way from Double-A to Triple-A and has a combined .298/.425/.551 line this year with 18 homers. His career .543 slugging percentage points to this season not being a fluke. The power is legit, and it should earn Alonso a shot at Citi Field soon.
Dropped out: Senzel, 3B/2B, Reds (Previous rank: 4)