Tuesday marks the 13th day of the 2021 season, and there's nothing special about that. But the 16th day is crucial. After 16 days, a player who makes his major-league debut can stay for the rest of the season without banking a full year of service time. In other words, his parent club gets another year of control.

When you hear about service-time manipulation, that's usually what it's referring to. By holding out 2-3 weeks at the start of a season, a team can get nearly the full benefit of a top rookie for the current year while also enjoying a seventh year, presuming he sticks around that long. It may not be so fair to the player, but the economic benefit is too great for most teams to resist.

Enough grievances have been raised in recent years that teams can no longer be so blatant about it, so I doubt we see a rush of high-impact call-ups on Saturday. But on Monday or later that same week? Possibly.

Some of the most likely candidates are some of the most widely rostered already, with Jarred Kelenic, Wander Franco and Alex Kirilloff in particular standing out. Kelenic and Franco should certainly be stashed in all leagues already, so make sure they're not still available in yours.

The names further down this list are less urgent and less assured of making an impact, but if you play in a deep enough league and are shooting for upside, you'll probably benefit from stashing them. I expect all 14 to contribute at some point in 2021.

1. Jarred Kelenic, OF, Mariners

2019 minors: .291 BA (443 AB), 23 HR, 20 SB, .904 OPS, 50 BB, 111 K
2021 spring: .300 BA (20 AB), 2 HR, 2 2B, 1.140 OPS, 4 BB, 1 K

Jake Fraley is hurt and Taylor Trammell has been buried by strikeouts, so it's not like the Mariners would be forcing the issue by promoting their top prospect, who looked polished beyond his 21 years even while losing time to a hamstring injury this spring. He was at the center of a controversy involving ex-president Kevin Mather, who was ousted for making some comments regarding service-time manipulation, so the Mariners may be extra cautious not to promote him precisely at the magic date. Still, expect him up before May.

2. Wander Franco, SS, Rays

2019 minors: .327 BA (425 AB), 9 HR, 27 2B, 18 SB, .885 OPS, 56 BB, 35 K
2021 spring: .257 BA (35 AB), 1 HR, 1 2B, .669 OPS, 1 BB, 7 K

The Rays kept Franco around late into camp and gave the consensus top prospect plenty of looks at third base, where he'd most naturally fit in the major-league lineup. Between that and having him travel with the team for the World Series last year, they must think he's close. They don't profile as an offensive juggernaut this year either, so they could genuinely use his bat in the lineup. His spring stats were merely so-so, but the strikeout rate suggests he wasn't overmatched.

3. Sixto Sanchez, SP, Marlins

2019 minors: 8-6 2.76 ERA, 1.07 WHIP, 1114 IP, 21 BB, 103 K
2020 majors: 3-2, 3.46 ERA, 1.21 WHIP, 39 IP, 11 BB, 33 K
2021 spring: 8 IP, 5 H, 1 ER, 2 BB, 3 K

The good news is we already know he's major league-ready thanks to his fine work last year. The bad news is we also know he's weeks away after being shut down with shoulder inflammation at the alternate training site. The expectation when he was left off the opening day roster was that he'd join the rotation as soon as a fifth starter was needed in mid-April, but mid-May seems more likely now. He's back to throwing at least, if only from 45 feet.

4. Alex Kirilloff, OF, Twins

2019 minors: .283 BA (375 AB), 9 HR, 18 2B, .756 OPS, 29 BB, 76 K
2021 spring: .129 BA (31 AB), 1 HR, 1 2B, .440 OPS, 1 BB, 8 K

The presumptive left fielder at the start of camp couldn't get going this spring, leaving the Twins with no choice but to send him down until he finds his timing. "What we really want is for Alex to start his career at the major-league level on a good note," manager Rocco Baldelli said, "where he is feeling good, he is locked in and he is ready to go and never look back." The way Luis Arraez, originally pegged for a bench role, has entrenched himself at the top of the lineup, though, presents something of a complication. Kirilloff projects as a middle-of-the-order bat, profiling for average and power.

5. Jo Adell, OF, Angels

2019 minors: .289 BA (305 AB), 10 HR, 7 SB, .834 OPS, 30 BB, 94 K
2020 majors: .161 BA (124 AB), 3 HR, 4 2B, .478 OPS, 7 BB, 55 K
2021 spring: .250 BA (20 AB), 2 HR, 1 SB, 1.023 OPS, 6 BB, 6 K

Losing Dexter Fowler for the year with a torn ACL leaves the Angels with a gaping hole in right field that they turned to Adell to fill last year. It's why he no longer qualifies as a rookie, and it's why the Angels might delay his arrival into the summer. The concern is less about service time than performance, given how overmatched he looked in 2020, but manager Joe Maddon noted Adell's progress this spring. "His swing is so much shorter, his strides so much more under control," Maddon said. "Because his foot is getting down sooner, the bat's not moving around and wrapping as much."

6. MacKenzie Gore, SP, Padres

2019 minors: 9-2, 1.69 ERA, 0.83 WHIP, 101 IP, 28 BB, 135 K
2021 spring: 0-0, 4.91 ERA, 1.82 WHIP, 11 IP, 8 BB, 10 K

The Padres already have a vacancy in their starting rotation after losing Adrian Morejon to a forearm strain, but with Dinelson Lamet making progress at the alternate training site and Ryan Weathers already stretched out in the bullpen, I'm thinking it's not yet Gore's ticket to the big leagues. The left-hander is still regarded as the game's top pitching prospect, which earns him a lot of leash here, but his command issues at the alternate training site last year appeared to persist this spring.

7. Matt Manning, SP, Tigers

2019 minors: 11-5, 2.56 ERA, 0.98 WHIP, 133 2/3 IP, 38 BB, 148 K 
2021 spring: 9 P, 11 H, 5 ER, 5 BB, 8 K

A forearm strain kept Manning from joining Tarik Skubal and Casey Mize in the majors last year and put him at a distinct disadvantage when it came to securing a job this spring. But there's reason to believe, between the steady minor-league track record, the plus command and the three developed pitches, that he's actually the most polished of the bunch. The Tigers don't have an opening yet, but nobody in that rotation is fully entrenched either. It's possible Skubal or Mize is the one Manning replaces.

8. Logan Gilbert, SP, Mariners

2019 minors: 10-5, 2.13 ERA, 0.95 WHIP, 135 IP, 33 BB, 165 K
2021 spring: 2 IP, 2 H, 1 ER, 0 BB, 4 K

Losing James Paxton in his very first start of course puts a damper on the Mariners' six-man rotation plans, but they don't have to rush a prospect to the majors to meet the need. Maybe they would if they viewed themselves as contenders, but since they're more realistically still a year away, they'll have Nick Margevicius and Ljay Newsome hold down the fort until midseason. Granted, Gilbert doesn't have much left to prove in the minors, but they gave him only one start in spring training and will obviously want to curb his innings after the weirdness of 2020.

9. Bobby Witt, SS, Royals

2019 minors: .262 BA (164 AB), 1 HR, 9 SB, .670 OPS, 13 BB, 35 K
2021 spring: .289 BA (38 AB), 3 HR, .851 OPS, 2 BB, 10 K

There was about a five-day period in spring training when it looked like Witt might beat the odds and claim the starting second base job as a 20-year-old who had yet to play a game above Rookie ball, but then GM Dayton Moore sobered up and sent him down. Part of me thinks this ranking is too high given that Witt is expected to begin the year in A-ball, but there's a chance he moves quickly. The Royals are having him learn the outfield to give him another yet path, and it's still true that he held his own in spring training, even hitting a 484-foot home run.

10. Daulton Jefferies, SP, Athletics

2019 minors: 2-2, 3.42 ERA, 1.04 WHIP, 79 IP, 9 BB, 93 K
2020 majors: 2 IP, 5 H, 5 ER, 2 BB, 1 K  
2021 spring: 3-0, 1.50 ERA, 0.89 WHIP, 18 IP, 6 BB, 24 K

With Cole Irvin struggling and A.J. Puk sidelined by a strained biceps, Jefferies' debut is potentially around the corner. Of course, Mike Fiers, himself on the mend after a bout with hip inflammation, may have something to say about it. Jefferies was arguably the Athletics' most impressive pitcher in spring training, and many thought he already had the job locked up before a last-minute pivot to Irvin. He's not held in as high esteem as the other pitchers on this list, but his strike-throwing ability in the minors two years ago certainly stands out.

11. Nico Hoerner, 2B, Cubs

2019 minors: .292 BA (288 AB), 3 HR, 8 SB, .752 OPS, 22 BB, 32 K
2019-20 majors: .247 BA (186 AB), 3 HR, 3 SB, .571 OPS, 12 BB, 24 K 
2021 spring: .364 BA (44 AB), 2 HR, 3 SB, 1.055 OPS, 3 BB, 4 K

Hoerner began to live up to his power projection by opening up his stance this spring and seemed like a shoo-in for the starting base job given the amount of time he spent in the majors the previous two years. But in the end, the job went to David Bote, purportedly because he had a big spring, too, but more likely because the Cubs will gain a year of control if they can keep Hoerner down for a total of 36 days. We're one-third of the way there, so by the start of May, Hoerner could be back. There's the question of whether he's impactful enough to justify the stash, though, which is why he's only 11th on this list.

12. Jarren Duran, OF, Red Sox

2019 minors: .303 BA (519 AB), 5 HR, 46 SB, .775 OPS, 46 BB, 128 K
2021 spring: .340 BA (47 AB), 3 HR, 2 SB, 1.069 OPS, 2 BB, 19 K

Few prospects did as much to elevate their stock in spring training as Duran did, subverting his reputation as a slap-hitting speedster with a power output that seemed like a natural outgrowth. In addition to the three homers this spring, he had six doubles and one triple, showing off improved strength and loft. And yet he still has the speed to steal bases and the bat control to hit for average. There isn't a pressing need for Duran in Boston yet, particularly if Franchy Cordero amounts to anything, but seeing as he's already 24, he'll get his shot at some point.

13. Jeter Downs, SS, Red Sox

2019 minors: .276 BA (460 AB), 24 HR, 24 SB, .888 OPS, 60 BB, 107 K
2021 spring: .278 BA (18 AB), 2 HR, 1.020 OPS, 4 BB, 7 K

Downs made it all the way to Double-A two years ago and of course got development time at the alternate training site last year, so it's reasonable to assume he's on the verge of reaching the majors. He didn't slow his timetable with his performance this spring, and because he profiles as a second baseman, it's only career utilityman Enrique Hernandez (who of course could move to a different position if the Red Sox insist) standing in his way. I'm skeptical Downs will be a big base-stealer in the majors, but I like his combination of patience and power.

14. Heliot Ramos, OF, Giants

2019 minors: .290 BA (389 AB), 16 HR, 24 2B, .850 OPS, 42 BB, 118 K
2021 spring: .410 BA (39 AB), 3 HR, 3 2B, 1.143 OPS, 1 BB, 10 K  

The still-relatively-new Giants regime hasn't had a chance to promote many prospects yet, but it was pretty aggressive about welcoming Joey Bart (even though it backfired) when injuries forced its hand last year. While only 21, Ramos advanced to Double-A in 2019 and made a strong impression this spring, particularly with his opposite-field power. A slugging outfielder may not raise your interest as much as some of these other players, but with the Giants mostly running retreads out there, an opening will develop soon enough.