Prospect Heat Check: Baseball's best farm system belongs to ...

For all of the plaudits the St. Louis Cardinals and Minnesota Twins' farm systems receive, one longtime scout insists neither has the best cache of prospects around."It's the Pirates," he said. "And I'm not sure it's close."

The scout had just finished watching a start by 19-year-old Tyler Glasnow, a 6-foot-7 toothpick whose fastball already flashes upper-90s velocity. Frightening though it may be to think about how hard he'll throw once his 195-pound frame fills out, Glasnow is already pretty damn scary to Low-A hitters. Over his last 10 starts, opponents have managed 1, 0, 3, 2, 1, 2, 1, 2, 2 and 2 hits. That's 16 in 42 2/3 innings, with 66 strikeouts.

Certainly there is polish left to apply for this Heat Check ace – Glasnow has 32 walks over those 10 starts, too – but his ascent this season is representative of where the Pirates' farm system has gone under general manager Neal Huntington, farm director Kyle Stark and lead international scout Rene Gayo. Rightfully maligned for using boot-camp training exercises on minor league players, the Pirates weathered the bad press and boast an array of top-level talents beyond Glasnow, whom they stole in the fifth round of the 2011 draft.

Beyond hitting on later-round picks – they also got pop-up starter Nick Kingham in the fourth round in 2010 – they've done well with top-of-the-draft selections after so many years of ineptitude. Jameson Taillon (No. 2 overall in 2010) and Gerrit Cole (No. 1 overall in 2011) could be the sort of reinforcements that help push the Pirates more toward playoff legitimacy than their lucky start in which their record is far greater than the more indicative run differential.

Before the latest collective-bargaining agreement capped draft spending, the Pirates spent $5 million on outfielder Josh Bell – and after an injury-wrecked 2012, he's reasserting himself as a prospect alongside Glasnow in Low-A.

A level above is center fielder Gregory Polanco, who along with shortstop Alen Hanson represents the fruits of Gayo, whom the movie "Pelotero" turned into a villain for his role in the pursuit of uberprospect Miguel Sano as a 16-year-old in the Dominican Republic.

The system might be the best around already. Imagine it with Sano and Mark Appel, who could go No. 1 overall in Thursday's draft after not signing with the Pirates, who took him with the eighth pick last season.

As it stands, the Pirates are more than happy with their booty, and because of Appel's spurning they've got the ninth overall pick in addition to the 14th in this year's draft. While this season may be another small-sample hangover waiting to happen, the future is anything but. The Pirates are going to be very, very good.

Coming soon

Last Heat Check we highlighted Michael Wacha, Jurickson Profar, Alex Wood and Yasiel Puig, all of whom are now in the big leagues. With the Super 2 cutoff approaching, teams are going to be far likelier to bring their best prospects to the big leagues. These six may well be up by the All-Star break.

Wil Myers, OF: Now this is more like the guy for whom the Rays gave up James Shields. Over his last 10 games, Myers is hitting .432/.458/.955 with five home runs and 19 RBIs. Even if they've got an outfield rotation of Ben Zobrist, Matt Joyce, Desmond Jennings and Kelly Johnson, the Rays will find room for the 22-year-old Myers.

Anthony Rendon, 2B: Danny Espinosa's struggles haven't gone away, so Rendon is coming to Wally Pipp him. His .466 on-base percentage between Double-A and Triple-A is perfect to stick near the top of the Nationals' lineup, and a team resurgence coinciding with his arrival would surprise no one.

Kyle Gibson, RHP: Closer Glen Perkins has thrown 20 2/3 innings, the 12th most for the Twins. He leads the team with 33 strikeouts. Perhaps it's time to summon the 6-foot-6 Gibson, fully recovered from Tommy John surgery and ready to infuse at least a little swing-and-miss into a Twins staff in desperate need.

Zack Wheeler, RHP: With 31 strikeouts and nine walks in his last six starts, the control issues of early in the season have vanished. The 23-year-old is more than ready, and as long as he and Matt Harvey stay healthy, the Mets finally have reason for optimism.

Christian Yelich, OF: If a 21-year-old with a gorgeous left-handed swing plays in a stadium with a fish tank that nobody goes to, did he really play in a stadium with a fish tank? Soon enough Yelich will be called upon by the existential crisis that is the Miami Marlins.

Sonny Gray, RHP: Like an Oakland predecessor, Gray is short, has a lively fastball, gaudy ground ball rates and plenty of strikeouts. He's not Tim Hudson, per se, but he is ready to join an A's team whose pitching will carry it.

Come not quite as soon but soon enough

Archie Bradley, RHP: Just your old ho-hum 1.18 ERA over 12 starts. After thrashing High-A hitters, the Diamondbacks promoted Bradley to Double-A – and his ERA has been even better in seven starts there. Scouts think Bradley could pitch in the big leagues today. With Patrick Corbin, Ian Kennedy, Brandon McCarthy, Trevor Cahill and Wade Miley in the rotation now, Daniel Hudson soon to replace one of them and Tyler Skaggs and Randall Delgado ready in the minors, he'll have to wait. Though, if he keeps pitching like this, it won't be very long.

Anthony Ranaudo, RHP: After pitching in nine games last season and walking as many as he struck out (27) in 37 2/3 innings, Ranaudo is healthy and more than back. Once considered a potential No. 1 overall pick, he fell to the 39th pick in 2010 where the Red Sox paid him an over-slot bonus. Now, in 10 starts, he's 6-1 with a 1.48 ERA and the sort of peripherals (54 2/3 innings, 31 hits, three homers, 15 walks, 58 strikeouts) that scream excitement.

Promote me, please

Miguel Sano, 3B: The power has cooled down some, but a .337/.431/.637 season line at High-A shows he's ready to move up. Barring a disastrous showing there, Sano is on track to arrive next June as a 21-year-old – and the best Twins prospect since Joe Mauer.

Byron Buxton, CF: His companion in Twins awesomeness is at .333/.435/.545 in Low-A with incredible speed and a tremendous arm. When he arrives in 2015, the Twins could be very, very dangerous.

Robert Stephenson, RHP: With 77 strikeouts and 16 walks over 59 2/3 innings, the Reds' flamethrower is more than ready for High-A after embarrassing hitters in Dayton.

Garin Cecchini, 3B: His .469 on-base percentage is the second highest in the minor leagues, and even though the Red Sox have gone level-by-level with him, one scout puts it succinctly: "They need to see him at Double-A to make sure he can replace [Will] Middlebrooks."

Stetson Allie: The former Pirates bonus baby never found the strike zone with his 100-mph fastball and switched to first base last season. Now he leads the minor leagues with 136 total bases. Still, he's a 22-year-old at Low-A, which is to say: Time for a challenge.

Watch out, Billy

Micah Johnson, 2B: With an ever-present green light, Johnson is outswiping stolen-base champion Billy Hamilton this season. Johnson has 47 steals to Hamilton's 30, though Johnson's been caught 13 times – and by Low-A catchers. He's already 22 and with top-end speed should be abusing the level like he is. While Hamilton's record of 155 last season almost certainly is safe, Johnson's emergence as a potentially dynamic player is exactly what a bereft White Sox farm system needs.

Turd of the Month

Josh Sale, OF: Don't think many would take offense if someone happened to chuck a coin or two at the Rays prospect once he returns from his suspension.

Better story

Kirby Yates, RHP: For the last five years, Yates has done nothing but strike out hitters in the Rays' minor league system. He's only 5-foot-10. He's a Tommy John survivor. He's got something of an unorthodox delivery that gets his fastball into the mid-90s. Nobody took him in the Rule 5 draft when he was exposed. But with 46 strikeouts in 26 1/3 innings at Triple-A Durham this year, following last year with 94 in 68 innings, he's a prime candidate for a call-up should the Rays look to overhaul a bullpen that ranks 22nd in ERA. And if not Yates, perhaps it will be Juan Sandoval, the inspiring blind-in-one-eye right-hander who recently was promoted to Triple-A and has a 2.91 ERA in 34 innings this season.

Help's on its way, Houston

George Springer, CF: The question when Springer left the University of Connecticut: Could he make enough contact in pro ball to allow his toolset to shine? The answer: That may not have been the best question. Because the two are not necessarily mutually exclusive. Springer still strikes out way too much: 66 times in 197 at-bats. He's also destroying Double-A pitching, with a minor league-leading 17 home runs and triple-slash of .310/.417/.640. His absurd .466 batting average on balls in play is going to fall, of course. When it does, the question is whether Springer can lessen the whiffs, too, to keep his bat from fading along with it.

Jarred Cosart, RHP: Arrived in the Hunter Pence deal and may well arrive in the big leagues soon, too. While his command still leaves something to be desired – 29 walks in 54 1/3 innings – he's striking out more than a hitter an inning and has allowed just two home runs. His familiarity with the strike zone will determine whether he ends up pitching the first six innings or the final one.

Mike Foltynewicz, RHP: Similar to Cosart, with a huge arm (he hits 100 mph regularly as a starter) and a flagging knowledge of where the ball is going. Lots of strikeouts. Lots of ground balls. More than holding his own at Double-A as a 21-year-old.

Lance McCullers, RHP: Part of the strategy in drafting Carlos Correa first overall last season was to divert money to later-round picks. McCullers was one of those, and one scout said: "He may make picking Correa worth it." McCullers has been a groundball machine at Low-A Quad Cities, not allowing a homer in 47 2/3 innings and striking out more than a batter an inning.

Remember this name

Chris Taylor, SS: The power may be something of a Cal League mirage – he plays in High Desert, the bat-juicingest home park in pro ball – but one scout who saw Taylor recently thinks he's a legit major leaguer. "He's got at least gap power, he's quick as hell and he's got great instincts," the scout said. Double-A is next for the University of Virginia product, and it may prove whether he's the one to replace Brendan Ryan.

It is not easy to be this bad

Melky Mesa, OF: No longer is the 26-year-old Mesa considered much of a prospect, and perhaps it's because of these three numbers: 214 plate appearances, 85 strikeouts, six walks.

Just because

Rock Shoulders, 1B: Our hero has fallen on hard times. While a .272/.373/.528 season slash line is nothing to spit at, he's 0 for his last 16 and 3 for his last 35. Of course, two of those three hits were home runs. And he is still named Rock Shoulders, so he wins.

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