There may be no Minor League Baseball games yet, but that's not going to stop us from dreaming about lineups.
In the coming weeks, Toolshed will craft the best possible prospect lineups, sorted by age. The opening edition focused on teenagers. This time, we turn our attention to prospects entering their age-20 seasons. Eligibility is determined by a player's age on June 30, roughly the midpoint of a regular season -- the same date used by Baseball-Reference in its age calculations. Also, to keep this as clean as possible, a player will only be placed at his primary position, with an exception of a designated hitter spot. As fun as it would be to move around shortstops or put third basemen across the diamond at first to get their bats in the lineup, such moves wouldn't fit the spirit of the exercise.
With those ground rules set, here is the most prospect-laden roster of age-20 players headed into 2020:

Catcher -- Ivan Herrera, Cardinals: The St. Louis backstop is the only non-Top-100 prospect on this list, but he may have enjoyed the largest surge in 2019 to earn his spot here all the same. Herrera signed for $200,000 out of Panama in July 2016, entered 2019 as the Cardinals' No. 20 prospect and now sits at the No. 4 spot heading into the 2020 season. The right-handed slugger has been a solid hitter at every stop through three seasons in the Minors, and that continued with his jump to the full-season levels last year. Herrera hit .284/.374/.405 over 87 games between Class A Peoria and Class A Advanced Palm Beach, and he didn't hurt his case by going 11-for-34 (.324) against tougher competition in the Arizona Fall League. His defense has grown to the point where he could be above-average behind the plate, particularly when it comes to his arm. His power isn't there yet, but it could be coming as he matures. With the rest of this lineup, that particular skill won't be much of a worry anyhow. Any lineup of any age would welcome a well-rounded catcher of Herrera's caliber.
First baseman -- Triston Casas, Red Sox: Here comes the pop. The Red Sox had dreams of keeping Casas at third base when they took him 26th overall in 2018, only to see him move across the diamond in his first full season. No matter. He's now the game's third-best first-base prospect and the No. 77 overall prospect in the game, per MLB.com, despite the move. That's because his offensive potential from the left side is that good. Casas hit 19 homers and produced a .472 slugging percentage and .820 OPS over 118 games for Class A Greenville last season, and if those numbers don't jump off the page, consider that all three placed among the top six in the South Atlantic League, where he was 2 1/2 years younger than the average player. Further, Casas' .218 ISO was third-best among all Class A sluggers in 2019. The pop is real and expect to see more of it as he gets older and moves to more hitter-friendly environs. It doesn't hurt that Casas can field his new position well and show a plus arm when it's pressed into service. Prospect's value can take a hit if they're moved to first. That hasn't been the case with Casas, making him one of the easiest picks for this lineup.
Second baseman -- Xavier Edwards, Rays: Where Edwards will eventually land in the field is still up in the air. The Padres took him as a shortstop, allowed him to play more second than short in 2019 and then moved this offseason to the Rays, an organization already loaded with middle-infield prospects. For now, he makes the keystone for the age-20 squad and (spoiler alert for the lineup below) also makes the club at the leadoff spot. Fewer than two years into his pro career, MLB.com's No. 72 overall prospect already has an impressive ability to reach base and make a good amount of contact as a switch-hitter. The standout skill will be his plus-plus speed, which helps him pick up infield hits (helpful for someone who puts the ball on the ground a lot) and his fair share of stolen bases. That could even get him some looks in center field at some point. For now, his range fits comfortably up the middle at second, and everyone behind him in this theoretical lineup should keep him burning around the basepaths.
Third baseman -- Nolan Gorman, Cardinals: More thump. Gorman's power was already well-known when he went 19th overall in 2018, and it's only because of that hype that his 15 homers and .439 slugging percentage between Peoria and Palm Beach last year felt like slight letdowns. Strikeout rates around the 30 percent mark at both stops didn't help matters, but that aside, he still posted a wRC+ above 100 at each stop. That's promising for a player who entered his first full season at just 18 years old. (He'll turn 20 on May 10, making him eligible for this list.) MLB.com's No. 47 overall prospect also still shows top-of-the-line raw power, and his defense has improved to the point where he looks more likely than ever to stick at third. In fact, only Alec Bohm, Ke'Bryan Hayes and Nolan Jones -- all of whom are at least two years older than Gorman -- rank higher among third-base prospects on MLB.com's list.
Shortstop -- Bobby Witt Jr., Royals: With a June 14, 2000 birthdate, Witt was on the older side of last year's Draft prep class. He was also the first high schooler taken in 2019 going second overall, so that speaks volumes about his current and future abilities. It isn't often that these sections start with defense, but Witt can be an exception with the plus range and impressive arm that make him a shoo-in to stay at the premium position at short. There is potential in the bat, even if it's behind the glove right now, and his exit velocities in the Rookie-level Arizona League back those up better than his numbers. He could be an above-average hitter with plus power in time. Altogether, that works out for a shortstop with true five-tool potential, making Witt the selection here as well as MLB.com's No. 10 overall prospect entering what would be his first full season.
Outfielders
Jarred Kelenic, Mariners: There's no doubt about the star of this group. Kelenic is one of only three selections here to have reached Double-A so far, and he's done so with easily the most success. The Mariners got aggressive with the left-handed slugger, who doesn't turn 21 until July 16, and reaped the rewards by seeing Kelenic hit .291/.364/.540 with 23 homers and 20 stolen bases over 117 games across three levels. His wRC+ was above 129 at each stop, and he managed a .542 slugging percentage at Double-A Arkansas, despite being roughly five years younger than the average Texas Leaguer. All five of Kelenic's tools have above-average potential, and his overall hitting, running and throwing are all considered plus. The only quibble might be that he has to move from center to right for this group, but that's minor considering his arm should be a weapon from that spot. He has become the focal point of Seattle's rebuilding effort -- even if All-Teenage Team outfielder Julio Rodriguez has some claim to that as well -- and his trajectory has the Majors closer in reach than anyone would have expected for a player playing his prep ball in Wisconsin this time two years ago. 
Alek Thomas, D-backs: Taking that center-field spot is another gifted fielder in MLB.com's No. 49 overall prospect. Thomas draws plenty of praise for his plus speed, and though he has a below-average arm, the amount of ground he covers up the middle more than makes up for it. That said, Thomas' best abilities might still be on the offensive side. After hitting .333 with an .858 OPS across two levels in his first Minor League campaign, the left-handed hitter kept things going with another strong start at Class A Kane County, where he produced a .312/.393/.479 line over 91 games. His numbers dipped slightly at Class A Advanced Visalia, but those early offensive results made many wonder why the Chicago-area native dropped to the second round in 2018. 
Heliot Ramos, Giants: Even though he was a first-round pick in 2017, Ramos sneaks onto this list since he won't turn 21 until Sept. 7. He will fit comfortably in left field next to Kelenic and Thomas, thanks to a plus arm that will probably have him in the other corner for most of his career. Ramos' most promising abilities are of the offensive variety, and after a rough first full season in which he was overmatched, he bounced back nicely in 2019, hitting .290/.369/.481 with 16 homers in 102 games between Class A Advanced San Jose and Double-A Richmond. Those 16 blasts were a career high, and with the growth he's shown in power, he's capable of touching double that at his ceiling in the Majors. Ramos is average across the board otherwise, but he's not below-average in anything either. Along with Joey Bart and Marco Luciano, he gives San Francisco one heck of a three-headed monster at the top of its farm system. He does the same with Kelenic and Thomas in this age-20 outfield.
Designated hitter -- Brett Baty, Mets: A thumper with some questions about his future defensive home? Sounds like a good fit for the DH. Baty knows a little about that life already, despite being drafted 12th overall last June. The Texas native was especially old for his class and turned 20 in November. It's possible if he was a little younger, he could have cracked the top 10. The left-handed slugger has already shown off a solid approach and good power with a .368 OBP, .452 slugging percentage and 25 extra-base hits in 51 games across three levels, the top being Class A Short Season Brooklyn. Strikeouts could be an issue, but the power alone has the chance to make up for it. Given his size at 6-foot-3, 210 pounds, it's a question of whether he'll move over to first someday soon like Casas did, but we don't have to worry about that here. Put Baty in the Age-20 Home Run Derby next to Casas, Gorman and Kelenic, and you'll get a show.
Right-handed pitcher -- Luis Patiño, Padres: For all the talk about power hitters, it makes sense that one of the options on the mound is a pretty good power pitcher in his own right. At No. 8 overall, Patiño is the highest-ranked righty pitching prospect in this group and for good reason. His fastball sits in the mid-90s but is plenty capable of touching higher with plenty of movement to boot. His slider also earns plus grades, and his curveball and changeup round out the full package. What's more, his control is impressive, having struck out 123 and walked only 38 over 94 2/3 innings between Class A Advanced Lake Elsinore and Double-A Amarillo last season. At his listed size of 6-foot, 192 pounds, Patiño may not look the part of dominant starter. That is, until anyone sees his stuff.
Left-handed pitcher -- Matthew Liberatore, Cardinals: Liberatore gives the Cardinals three prospects in this group, having just joined the club in a trade from the Rays this offseason. Upon his arrival, MLB.com's No. 58 overall prospect gave St. Louis a much-needed star pitching prospect. His bread-and-butter is his plus curveball, but his fastball, capable of touching the mid-90s, is considered a plus pitch as well. Like Patiño, Liberatore works in total with a four-pitch mix and decent control. The 6-foot-5 southpaw might lack the knockout heat of his right-handed counterpart, but the overall package still points to a future spot in a Major League rotation. Of note: he's the youngest ranked among MLB.com's top 10 left-handed pitching prospects.
Preferred batting order
2B Edwards (S)
SS Witt (R)
RF Kelenic (L)
3B Gorman (L)
1B Casas (L)
DH Baty (L)
C Herrera (R)
CF Thomas (L)
Edwards' speed gives him the edge over Thomas for the leadoff spot, leaving the Arizona outfielder to bat ninth if only to get his speed in front of Witt, Kelenic et al. as well. That middle of the order presents opportunities to go deep with every plate appearance. It's also heavy on left-handers. While it was tempting to slip Witt into the middle of the pack for some balance, his overall skill set was too tempting to keep out of the top spots in the lineup. 
Toughest omissions
The positions usually reserved for the game's most talented players led to some expected logjams on the Age-20 Team. Shortstop was predictably loaded, and if not for Witt, Top-100 prospects Jordan Groshans, Geraldo Perdomo and Luis Garcia -- not to mention other notable names like Brice Turang and Jeremiah Jackson -- would have made for a tougher debate. Similarly, at the right-handed pitching spot, No. 36 overall prospect Grayson Rodriguez and No. 53 Hunter Greene could have made for an interesting discussion, but No. 27 Patiño took that cake walking away. Pour one out for Cubs outfielder Brennen Davis, who surged to the No. 78 overall spot after his first full season but couldn't quite sneak in past Ramos for the final spot on the grass. Finally, the catching position left Bo Naylor (Indians) and Gabriel Moreno (Blue Jays) on the outside looking in, but both could sneak in past Herrera with strong performances to come.