September call-ups are all hype.

Maybe there was a time not too long ago when clubs introduced their best prospects that way, but economically speaking, it's one of the least opportune times to do so, particularly for the ones so good that it wouldn't make sense to send them back down.

Why wouldn't a contender call them up earlier and get more out of that extra season of team control? Why wouldn't a non-contender call them up later, like the middle of next April, and get the absolute most out of that extra season?

What's often made out to be a flood of new and exciting talent is really just a bunch of the same prospects who we've already gotten a chance to see this year — and in similarly inconsequential roles — or a bunch players who are more organizational depth than true prospects.

But wait, didn't Victor Robles and Francisco Mejia get the call last September? Sure, and they had 37 at-bats between them. They played bit roles for contending clubs, which was justified because of both the stakes and the fact they didn't look like they'd have jobs waiting for them next April. It wasn't a countdown situation like for Ronald Acuna this April or Kris Bryant in April 2015. A little service time for Robles and Mejia at the end of 2017 didn't jeopardize their teams' plans for them in 2018.

It's a guessing game, for the most part. A few teams have already revealed their plans for particular players, but the rest are keeping it close to the vest. All we have to go on, then, is intuition, and my intuition has given me five potential call-ups who I think might contribute in Fantasy, five who might not and five who probably aren't happening at all.

Truth is the surprise September performances are more likely to come from players who are already in the majors.

Ready to play and play often

(If any September call-ups are going to make a Fantasy impact, it's these five.)

Austin Meadows, OF, Rays

2018 minors: .293 BA (256 AB), 9 HR, 12 SB, .829 OPS, 17 BB, 36 K
2018 majors: .292 BA (154 AB), 5 HR, 4 SB, .795 OPS, 8 BB, 35 K     

Meadows looked good in his time with the Pirates early this year, making consistent contact with at least a hint of power, and he has actually lived up to his top prospect standing since joining the Rays' Triple-A affiliate in the Chris Archer trade, batting .319 (29 for 91) with seven homers and a 1.040 OPS in 26 games. With the opportunities he has already gotten, there are no service time games left for the Rays to play, and while it's not clear he has a path to at-bats, especially once Mallex Smith returns from illness, about the only fixtures in the Rays lineup right now are Tommy Pham, Kevin Kiermaier and Willy Adames.

Christin Stewart, OF, Tigers

2017 minors: .256 BA (485 AB), 28 HR, 86 RBI, .836 OPS, 56 BB, 138 K
2018 minors: .255 BA (435 AB), 23 HR, 75 RBI, .830 OPS, 65 BB, 103 K    

Stewart isn't actually on the 40-man roster yet, but a number of Tigers beat writers have expressed optimism that the 24-year-old will be among the players joining the team in September, which is notable mostly because the Tigers lineup can use all the help it can get. Stewart is far from a can't-miss prospect, but he'll work the count and has plenty of power to spare. The likelihood of him getting regular at-bats gives him a leg up over most prospective call-ups, so if you missed out on Hunter Renfroe or Tyler O'Neill, here's another option for cheap power.

Francisco Mejia, C, Padres

2017 minors: .297 BA (347 AB), 14 HR, 21 2B, .835 OPS, 24 BB, 53 K
2018 minors: .284 BA (408 AB), 12 HR, 28 2B, .779 OPS, 25 BB, 78 K     

September presents the Padres with an opportunity to evaluate what they have in Mejia, whose viability behind the plate is often called into question and whose bat hasn't been totally reliable over the past couple years. But over his past 64 games, more than half of which came in the Indians organization, he has hit .346 with nine homers and a .930 OPS, which is more befitting his talents than what we saw during the first two months of this season and the last two months of last season. Obviously, any catcher with an ounce of offensive potential is of interest in Fantasy, so even if he's forced to split at-bats with defensive specialist Austin Hedges, Mejia could be usable.

Touki Toussaint/Bryse Wilson, SP, Braves

Toussaint minors: 9-6, 2.38 ERA, 1.13 WHIP, 136 1/3 IP, 53 BB, 163 K
Wilson minors: 8-5, 3.32 ERA, 1.17 WHIP, 124 2/3 IP, 36 BB, 141 K    

I lump these two together because I honestly don't know how to separate them. I don't know which one the Braves prefer, and I don't know that it matters after each fared well enough in a spot start, Toussaint allowing one run over six two-hit innings against the Marlins and Wilson throwing five shutout innings against the Pirates, to earn another chance. Wilson has begun to work out of the bullpen some at Triple-A, which perhaps tips the scales slightly in Toussaint's favor, but I suspect they'll both have a chance to start once or twice in September. Stashing them seems a bit presumptuous, particularly in mixed leagues, but if you have the foreknowledge of when they'll be starting, you might get some use out of them.

Joshua James, SP, Astros

2017 minors: 4-8, 4.38 ERA, 1.46 WHIP, 76 IP, 32 BB, 72 K 
2018 minors: 6-4, 3.23 ERA, 1.12 WHIP, 114 1/3 IP, 49 BB, 171 K      

The Astros have pretty much abandoned the idea of reintroducing Lance McCullers to the rotation once he's recovered from a strained forearm — there just won't be enough time to build him back up — which means they still have an opening to fill. Two, actually, now that Charlie Morton is sidelined by shoulder discomfort (though he's only expected to miss one turn). Framber Valdez got a turn last time through the rotation, but Josh James has more to offer, boasting the best strikeout rate for any pitcher with more than 15 starts and a fastball that pushes triple digits. The right-hander has had a breakout season, and seeing as he's already 25, the Astros need to start redeeming that value.

Maybe they will, but will it matter?

(These prospects likely will see some action in September, but probably not enough to make a real Fantasy contribution.)

Kyle Tucker, OF, Astros

2018 minors: .327 BA (391 AB), 14 HR, 14 SB, .886 OPS, 36 BB, 70 K
2018 majors: .154 BA (52 AB), 1 3B, 1 2B, 1 SB, .466 OPS, 5 BB, 11 K 

Tucker has gotten two stints with the Astros already this year. The first looked like it'd be for keeps in July, but they ran out of patience, sent him down and brought him back only briefly when they needed an extra body in mid-August. All he has done since that latest stint is hit .420 (29 for 69) with 10 homers and six steals, and yet his path to everyday at-bats is more obstructed than ever now that Marwin Gonzalez is slugging again and Tyler White has forced his way into the lineup. Seems like it'll be just spot duty for Tucker, if that. 

Franklin Barreto, SS, Athletics

2018 minors: .260 BA (269 AB), 18 HR, .890 OPS, 39 BB, 100 K
2018 majors: .246 BA (61 AB), 4 HR, .778 OPS, 1 BB, 25 K  

After the way his previous stints in the majors have gone, you probably aren't terribly enthusiastic about the prospect of a Barreto return, but his monstrous numbers in August — a .366 batting average with eight home runs and a 1.216 OPS — might change your tune. As with his previous stints in the majors, though, the Athletics aren't able to commit a spot to him with Matt Chapman, Jed Lowrie and Marcus Semien more than holding their own around the infield. The 22-year-old may have renewed dynasty appeal, but there isn't a path for him in redraft leagues.

Willie Calhoun, OF, Rangers

2017 minors: .300 BA (486 AB), 31 HR, 27 2B, .927 OPS, 42 BB, 61 K
2018 minors: .299 BA (415 AB), 9 HR, 32 2B, .796 OPS, 31 BB, 45 K  

Calhoun was a trendy sleeper pick this spring, with many assuming he'd make the opening day roster, so the fact he's still toiling in the minors is probably a great source of frustration for some. Given how much his home runs have fallen off at Triple-A Round Rock this year, though, I'm not sure he's worth it. He's still an intriguing bat, boasting an exceptional contact rate in addition to the dormant home run power, but he'll find the at-bats even harder to come by than when he was up with the Rangers for 22 games in July and August. Joey Gallo and Adrian Beltre aren't even getting to play every day.

Victor Robles, OF, Nationals

2017 minors: .300 BA (430 AB), 10 HR, 27 SB, .875 OPS, 37 BB, 84 K
2018 minors: .256 BA (168 AB), 2 HR, 17 SB, .698 OPS, 25 BB, 29 K   

The general belief among beat writers is that Robles will be up in September because, well, he was last year. And maybe getting a little more exposure to major-league pitching before presumably taking over for Bryce Harper next year will be the best thing for him, but it doesn't seem like he's up for the challenge now, having yet to regain his power stroke after missing the first couple months with a hyperextended elbow. He has shown good plate discipline and an ability to steal bases, but with Juan Soto and Adam Eaton occupying the other two spots in the outfield, the 21-year-old will again be limited to spot duty.

Justus Sheffield, SP, Yankees

2017 minors: 7-7, 3.12 ERA, 1.35 WHIP, 98 IP, 34 BB, 88 K
2018 minors: 6-6, 2.56 ERA, 1.17 WHIP, 112 2/3 IP, 50 BB, 119 K  

Yankees general manager Brian Cashman has been completely transparent about Sheffield's timetable and role. We know the left-hander will be up in September, and we know he'll work out of the bullpen, having recently shifted there at Triple-A Scranton/Wilkes-Barre. Could he make a spot start down the stretch? It's possible, but seeing as he wouldn't be stretched out and is inefficient to begin with, would it be of any benefit in Fantasy? He's just not in a position to make that sort of impact right now, and if he fares too well in relief, his short stature and pronounced control issues might make it easy to keep him there.

Don't count on it

(These prospects, despite our sincerest hopes, probably won't be getting the call at all.)

Vladimir Guerrero, 3B, Blue Jays

2017 minors: .323 BA (437 AB), 13 HR, 28 2B, .910 OPS, 76 BB, 62 K
2018 minors: .387 BA (336 AB), 19 HR, 27 2B, 1.088 OPS, 37 BB, 37 K   

What would possibly possess the Blue Jays to call up Guerrero now? They already know he's ready. He has maintained a batting average right around .400 all year with top-shelf power and unbelievable plate discipline. He's the next face of the franchise and someone they'll want to debut as early as possible next year. Calling him up now would only push that date back, and seeing as they have nothing to play for, the only gain would be on the PR front. 

Eloy Jimenez, OF, White Sox

2017 minors: .312 BA (333 AB), 19 HR, 22 2B, .947 OPS, 35 BB, 72 K
2018 minors: .343 BA (397 AB), 21 HR, 27 2B, .973 OPS, 30 BB, 64 K   

Jimenez is in the same boat as Guerrero, having obviously earned his place in the majors but having earned it so many months ago that you can only assume the White Sox are milking it, waiting to get the maximum possible benefit from suppressing his service time, which would mean promoting him in the middle of next April. There was some hope they might take a more aggressive approach after they called up their top pitching prospect, Michael Kopech, last week, but that move was a response to Kopech's improved performance. Jimenez's doesn't have any room for improvement, and here we are.

Peter Alonso, 1B, Mets

2017 minors: .289 BA (353 AB), 18 HR, .883 OPS, 27 BB, 71 K
2018 minors: .277 BA (451 AB), 33 HR, .955 OPS, 75 BB, 125 K    

The Mets have ended the suspense already, ruling out Alonso for a September promotion, according to The Athletic. Alonso has of course been one of the minors' most prolific power hitters this year — and in a way that was fairly predictable given how his average exit velocity rated similarly to some of the majors' best last year. He did struggle after a midseason promotion to Triple-A but has rebounded to hit .299 with 12 homers and a 1.053 OPS over his past 35 games. Supposedly, it's an at-bats issue. The Mets will spend September evaluating Jay Bruce, Dominic Smith and Wilmer Flores at first base before presumably turning the job over to Alonso early next season.

Forrest Whitley, SP, Astros

2017 minors: 5-4, 2.83 ERA, 1.21 WHIP, 92 1/3 IP, 34 BB, 143 K  
2018 minors: 0-2, 3.76 ERA, 0.99 WHIP, 26 1/3 IP, 11 BB, 34 K 

When Whitley was returning from his 50-game suspension for drugs (the non performance-enhancing kind) back in June, I argued that the time he missed might actually be a blessing since it would ensure his availability later in the season. But he came back throwing only four innings at a time, then missed a few weeks with an oblique injury and is now sidelined by a sore lat. The arm is so stellar that you could see why the Astros might want to have it on hand as they try to knock off the Athletics, but even if Whitley recovers in time, adding him to the 40-man roster and starting his service time clock after a year of so much tumult seems unwise, especially since his performance also leaves reason to wonder if he's up for the challenge.

Brendan Rodgers, SS, Rockies

2017 minors: .336 BA (372 AB), 18 HR, 26 2B, .940 OPS, 14 BB, 71 K
2018 spring: .267 BA (416 AB), 17 HR, 12 SB, .792 OPS, 31 BB, 91 K 

Rodgers' time is drawing closer, but he has played only 16 games at Triple-A and done nothing in them. The Rockies are already sure to bring Garrett Hampson back and will struggle to find him at-bats given that they're fighting for a playoff spot and, you know, Trevor Story and DJ LeMahieu are pretty good. Rodgers isn't necessarily someone they'd look to call up next April either, so I think September is out of the question.