If you didn't stash Oscar Taveras or Jon Singleton ahead of time, chances are you don't have them now.

That's because as soon as everyone heard they were coming up, the competition for their services escalated to where you didn't even have a shot at them. Someone else either won the race to the waiver wire in a simple add-drop league or blew half his budget in an FAAB league.

Most owned minor leaguers (as of 6/5)
Player Own %
1. Gregory Polanco, OF, PIT 83
2. Javier Baez, SS, CHC 46
3. Archie Bradley, SP, ARI 43
4. Andrew Heaney, SP, MIA 41
5. Noah Syndergaard, SP, NYM 38
6. Danny Salazar, SP, CLE 38
7. Byron Buxton, OF, MIN 35
8. Maikel Franco, 3B, PHI 33
9. Kris Bryant, 3B, CHC 33
10. Dylan Bundy, SP, BAL 28

I'm not talking about one of those 10-team Head-to-Head points formats where only half the owners are still paying attention. In those leagues, Singleton might still be unowned, given the depth at first base. But in anything deeper, Taveras and Singleton have the kind of talent that could shake up the standings, as both showed by homering in their debuts.

Granted, in terms of immediate impact, the Yasiel Puig types are few and far between, but even if Taveras and Singleton just make the kind of impact Wil Myers did last year, emerging as must-start options in the process, owning them at the moment of their arrival is like making a trade so outrageous that even the most lenient veto policies couldn't prevent an uproar.

And to think you could have been the one to benefit from it if you had just acted with a little foresight.

Of course, even worse than the initial mistake is a failure to learn from it. When that next game-changer arrives, you want to be the one with him already in your back pocket, having won the competition before it even begins.

So then, who's next? That's the appropriate question to ask here. Though Taveras and Singleton may have kicked off promotion season, more are sure to come.

Let's leave Gregory Polanco out of this discussion. He's 82 percent owned and has had so much written about him already that anyone still questioning whether or not to own him wouldn't benefit from this sort of list anyway. Plus, given the rumors he'll be up as soon as this weekend, he may not qualify for this list much longer.

Meanwhile, all the prospects listed here are owned in less than half of all Fantasy leagues.

1. Javier Baez, SS, Cubs

Between the .219 batting average, the .688 OPS and the 65 strikeouts in 169 at-bats, Baez's overall numbers at Triple-A Iowa are nothing short of terrible, which is especially surprising with him playing in the hitter-friendly Pacific Coast League. He appeared about ready to debut when he hit .264 (14 for 53) with five home runs this spring, and as Jon Heyman recently wrote, his disappointment in not making the team may have contributed to his struggles. He's been much better of late, though, batting .356 (21 for 59) with four home runs in his last 17 games, and is one of the players expected to benefit most from Manny Ramirez's expertise in working the count and squaring up a breaking ball. If he can overcome his mental hurdles, Baez is still on track to reach the big leagues this summer, most likely to man second or third base. And a shortstop-eligible player with his power potential (he hit 37 home runs between two stops last year) is as big as you'll find off the waiver wire this time of year.

2. Maikel Franco, 3B, Phillies

If you'll remember from last week's Prospects Report , Cody Asche's hamstring strain presented Franco with an opportunity to claim the starting third base job if he could just put together a hot streak at Triple-A Lehigh Valley. But he hasn't. As a matter of fact, in his last five games, he's just 3 for 21 (.143). Like Baez, he has hit much better in recent weeks than his overall numbers would suggest, but unlike Baez, his path to the majors ... well, it isn't exactly blocked, but Asche is more than just a seat warmer. Franco showed his potential by hitting .320 with 31 home runs, a .926 OPS and just 70 strikeouts in 541 at-bats between two stops last year and is clearly the player the Phillies want at third base long term. A convincing enough hot streak should be enough for him to push Asche aside, injured or not, but right now, mid-July seems more likely than mid-June.

3. Andrew Heaney, SP, Marlins

Starting pitchers typically don't make for the most stashable prospects in Fantasy since they usually face an innings limit of some kind, but those who made a play for Gerrit Cole, Michael Wacha and, to a lesser degree, Zack Wheeler last year were rewarded in the end. Heaney is already about 25 innings away from last season's total, which probably gives him not much more than 65 innings to go, but since the only thing standing between him and his big-league debut is a Randy Wolf meltdown, he should get most of those in the majors. The Marlins recently promoted him to Triple-A New Orleans, perhaps as a primer for the final leap, and though he's given up his share of hits there (who hasn't in the PCL?), he has maintained the kind of strikeout-to-walk ratio (18 to 1 in 17 innings) that lends itself to immediate success.

4. Joc Pederson, OF, Dodgers

Unlike the first two players on this list, Pederson is putting up the kind of numbers at Triple-A Albuquerque that make his prospect status apparent to all, batting .337 with 15 home runs, 13 stolen bases and a 1.071 OPS. Granted, his best minor-league seasons, including this one, have come in extremely hitter-friendly leagues, but he proved to be just as much of a power-speed threat, with a patient approach to boot, in between, batting .278 with 22 homers, 31 steals and 70 walks in 439 at-bats at Double-A last year. So why doesn't he rank higher on this list? Because unlike Baez and Franco, his route to the big leagues isn't so clear at this point. The ankle injury to Carl Crawford has reduced the clutter for now, but it figures to be a short-term issue. When he returns, the Dodgers are back to four outfielders for three spots -- and that's before even adding Pederson to the mix. Of course, most of those outfielders -- specifically, Crawford, Matt Kemp and Andre Ethier -- are on the wrong side of 30 and/or susceptible to injuries, so at some point in the next four months, two figure to be down at once. But no one can predict exactly when.

5. Kevin Gausman, SP/RP, Orioles

We got to see Gausman in the big leagues for an extended stretch last season and one start earlier this season, and the results were less than satisfactory. The stuff is apparent to anyone watching him pitch, but in only his second professional season, the fourth overall pick in the 2012 is still fleshing out his arsenal. The result is exactly what we saw in his May 14 start against the Tigers -- a few innings of dominance before hitting a wall the second or third time through the order, which explains why he was so much more effective as a reliever last year. He still shows the makings of something great with a 2.40 ERA in nine starts at Triple-A Norfolk and has gotten back to throwing strikes after struggling with his control earlier this year. He's not as exciting as the other four on this list simply because he has failed before, but he's still more likely than not to become a regular part of the Orioles starting rotation by season's end.

Stay in touch with the most passionate Fantasy staff in the business by following us on Twitter @CBSFantasyBB or Scott at @CBSScottWhite .