In the past, I might have told you September call-ups are overrated for Fantasy, that the biggest prospects generally don't arrive at that point in the season and that most teams use the extra roster space to bolster their bullpen and bench.

But that was before the new CBA, before the introduction of new incentives that could make September one of the most common times for impact call-ups.

Here's a phrase you've been hearing more lately: "retain rookie eligibility for next year." That's the key. The way it works is that teams get extra draft picks if their top prospects go on to place high in awards voting over the first several years of their career, but only if they were on the roster for their entire rookie season.

My hunch was that it wouldn't do much to address the service time manipulation that's come to govern prospect promotions in recent years, that the average GM would still value an extra year of service time over the possibility of an extra draft pick. But based on some of the names already called up and rumored to be called up, my hunch appears to have been wrong.

By waiting until September -- or just a little before -- an organization has a chance to break in a prospect without using up his rookie eligibility, putting him in a position to claim the opening day job next year and hopefully score a draft pick in the years that follow. A little foretaste makes the chances of a successful transition that much better.

So which prospects stand to benefit from this sea change? Who might be boon to your Fantasy team down the stretch? I've come up with 20 names here, grouped by likelihood of both getting the call and making a substantive difference. It's true some are already confirmed to be on the way, but I figured you'd like to hear about them just the same.

Already confirmed

Corbin Carroll, OF, Diamondbacks
R/AA/AAA: .307 BA (362 AB), 24 HR, 31 SB, 1.035 OPS, 67 BB, 107 K
He's already up and contributing but is clearly part of the wave I'm intending to highlight here. The 22-year-old needed only 142 games to climb the entire minor-league ladder, dominating every stop with a wide range of skills, but it's the hit tool, approach and speed that stand out the most. I expect he'll be my No. 1 prospect heading into next year.

Miguel Vargas, 3B, Dodgers
AAA: .304 BA (438 AB), 17 HR, 16 SB, .915 OPS, 71 BB, 76 K
Majors: 2 for 8, 2B, SB, K
The Dodgers have confirmed their top hitting prospect will be back in September -- and presumably for good this time -- but it may be a couple months too late. Max Muncy and Justin Turner have gotten their seasons back on track. Joey Gallo is now on board. The 22-year-old has shown he can bounce around the diamond, but the Dodgers will have to get creative to find him regular at-bats.

Hunter Brown, SP, Astros
AAA: 9-4, 2.55 ERA, 1.08 WHIP, 106 IP, 45 BB, 134 K
All it took was passable control for Brown to rocket up the prospect rankings, which says a lot about his stuff, namely the fastball. The Justin Verlander injury gives him a chance to make a start or two down the stretch, but more likely, he's here to audition for a bullpen role in the postseason.

Ken Waldichuk, SP, Athletics
AA/AAA: 6-4, 2.84 ERA, 1.16 WHIP, 95 IP, 36 BB, 137 K
While I've been pining for Waldichuk's promotion for the better part of two seasons, I'd have rather it come with the Yankees than with the Athletics. Still, he should take a regular turn in September, and we'll finally get to see if his funky left-handed delivery plays as well in the majors as it did in the minors.

Michael Toglia, 1B, Rockies
AA/AAA: .249 BA (429 AB), 30 HR, .851 OPS, 60 BB, 149 K
Toglia homered three times in his second-to-last game for Triple-A Albuquerque, and the power production has picked up in general. I'd be inclined to dismiss him because of the near-30 percent strikeout rate between Double- and Triple-A, but Coors Field is a magical place that can cover up a myriad of hitter flaws.

Potentially huge

Gunnar Henderson, SS, Orioles
AA/AAA: .297 BA (407 AB), 19 HR, 22 SB, .947 OPS, 79 BB, 116 K
After floating the idea for weeks, the Orioles have added Henderson to the taxi squad, which would suggest a promotion is just around the corner for the prospect several publications regard as the best in all of baseball. It's an aggressive move fueled in part by an unlikely playoff bid. While Henderson is a must in all Fantasy leagues for the upside, he did struggle some with strikeouts and same-handed pitchers at Triple-A.

Josh Jung, 3B, Rangers
R/AAA: .287 BA (94 AB), 9 HR, .994 OPS, 7 BB, 19 K
The Rangers haven't confirmed Jung is coming up Sept. 1 or added him to the taxi squad or anything like that, but he's the most obvious (and promising!) promotion candidate not to receive that treatment yet. He was in line to be the opening day third baseman before tearing the labrum in his non-throwing shoulder and has pummeled minor-league pitching since returning in late July.

Oswald Peraza, SS, Yankees
AAA: .257 BA (381 AB), 18 HR, 32 SB, .766 OPS, 32 BB, 98 K
GM Brian Cashman has gone on record to say he doesn't see an opening for Peraza, but Yankees fans have wanted the 22-year-old to replace Isiah Kiner-Falefa for months and may finally get their way once there's no longer the threat of him using up his rookie eligibility. Though his overall numbers are solid, he's performed at another level since mid-June, batting .314 with 13 homers, 21 steals an a .925 OPS in 51 games. Defense isn't thought to be an issue either.

Triston Casas, 1B, Red Sox
R/AAA: .279 BA (265 AB), 11 HR, 23 2B, .891 OPS, 49 BB, 68 K
Casas would probably be in the majors already if an ankle injury hadn't sidelined him for much of the summer. As it is, he's only found his footing over the past couple weeks, batting .385 (15 for 39) with more walks (12) than strikeouts (eight) over his past 11 games. Still, his age and experience level puts him in the mix for a starting job next spring, which gives the Red Sox incentive to call him up now.

Grayson Rodriguez, SP, Orioles
AAA: 5-1, 2.09 ERA, 0.84 WHIP, 56 IP, 14 BB, 80 K
The best pitching prospect in baseball was set to be called up around the same time as Adley Rutschman, but a strained lat derailed those plans. Because he's only now beginning a rehab assignment, it might make more sense to bring Rodriguez back as a reliever, but he says he intends to start every fifth day the rest of the way. There's still time for him to build up and take 3-4 turns in the majors.

Potentially helpful

Sal Frelick, OF, Brewers
A+/AA/AAA: .325 BA (391 AB), 7 HR, 18 SB, .863 OPS, 45 BB, 56 K
I'd like his chances to debut more if the Brewers hadn't already called up Garrett Mitchell to address their center field need. Frelick, their first-round pick just a year after Mitchell, is a higher-floor but lower-ceiling player, profiling as something like another Steven Kwan with a plus hit tool and some speed.

Mark Vientos, 3B, Mets
AAA: .286 BA (346 AB), 23 HR, .903 OPS, 41 BB, 111 K
It's interesting that the Mets opted to meet their recent third base need with Brett Baty, who had barely reached Triple-A, rather than Vientos, who had spent the entire year there. The latter has more than proven his power credentials at age 22, and for as good as his overall numbers look, he got off to a miserable start. Beginning May 1, he's batting .312 with 22 homers and a .974 OPS.

Ryan Pepiot, SP, Dodgers
AAA: 8-0, 2.58 ERA, 1.08 WHIP, 80 1/3 IP, 35 BB, 98 K
Majors: 2-0, 4.02 ERA, 1.40 WHIP, 31 1/3 IP, 22 BB, 36 K
With Clayton Kershaw on the verge of returning from a back injury, there doesn't appear to be an opening for Pepiot, but with the Dodgers cruising to a division title, they can afford to give him spot starts just to keep everyone fresh for the playoffs, particularly while Tony Gonsolin is sidelined. Walks have predictably been an issue for Pepiot in earlier stints, but his last start with the big club Aug. 21 was his best yet.

Gabriel Moreno, C, Blue Jays
AAA: .321 BA (221 AB), 2 HR, 16 2B, .815 OPS, 23 BB, 40 K
Majors: .276 BA (58 AB), 2B, .593 OPS, 2 BB, 7 K
Moreno performed adequately as a fill-in for Danny Jansen earlier this year and is rated as a top-five overall prospect by most publications, but the power that emerged last year has gone missing, even in the minors. It's also not clear how often he'd actually play if he's called up, being the third catcher and all.

Spencer Steer, 2B, Reds
AA/AAA: .274 BA (423 AB), 23 HR, .880 OPS, 51 BB, 89 K
One of the key pieces to come over from the Twins in the Tyler Mahle deal, Steer is a versatile player with a solid offensive profile, elevating and pulling the ball enough to get the most out of his middling power and also drawing walks at a nice rate. The Reds have a number of places they could break in the 24-year-old without impeding the development of other players.

Relative long shots

Alec Burleson, OF, Cardinals
AAA: .322 BA (410 AB), 20 HR, .890 OPS, 27 BB, 66 K
The 23-year-old clearly has an aptitude for hitting and has demonstrated enough power this year to profile for a corner outfield job in the big leagues. I wonder, though, what incentive the Cardinals have to call him up given Lars Nootbaar's emergence and Albert Pujols' resurgence. They don't even have a spot for Juan Yepez right now.

Enmanuel Valdez, 2B, Red Sox
AA/AAA: .297 BA (417 AB), 26 HR, .939 OPS, 57 BB, 103 K
If there was ever a time to call up Valdez, it was when Trevor Story was sidelined by a fractured wrist (which he's not anymore). It doesn't help that his numbers have gone in the tank at Triple-A Worcester, renewing concerns that his 5-foot-9 frame may not pack as much of a punch as it appeared to in the Astros system. Defense is also an issue.

Michael Busch, 2B, Dodgers
AA/AAA: .275 BA (454 AB), 27 HR, .884 OPS, 61 BB, 146 K
If the Dodgers can't find playing time for Miguel Vargas, they almost certainly can't for Busch, who's two years older but has struggled with his transition to Triple-A. The consensus top-100 prospect has begun to find his footing over the past couple weeks, though, cutting down on the strikeouts and bringing the walks closer to the levels we saw in his previous stops.

Justin Dirden, OF, Astros
AA/AAA: .322 BA (419 AB), 23 HR, 10 SB, 1.007 OPS, 48 BB, 117 K
It's surprising Dirden hasn't gotten more attention, given his production, especially since being a left-handed hitter and capable center fielder typically makes for an easier path. He's already 25, meaning there isn't much to wait for. The Astros did just demote Jake Meyers, which opens the door for a September surprise.

Matt Mervis, 1B, Cubs
A+/AA/AAA: .310 BA (419 AB), 27 HR, .972 OPS, 37 BB, 90 K
Most prospect evaluators haven't caught on to Mervis yet, possibly dinging him for going undrafted and being confined to first base, but it's clear he's the Cubs' future at the cold corner, being compared internally to Anthony Rizzo. And seeing as he's already 24, it wouldn't be the shock of the century to see that future begin now.