The pitchers on this list all turned in terrific seasons to jump much more firmly on the radar, pitching across multiple levels, often very young for the league they were in at the time. Some have gone from off the Top 100 prospects list to firmly on it, while others have leapt from the end of the list up close to the top.
Walker Buehler, RHP, Dodgers No. 1/MLB No. 10
Buehler might have been the first player taken from Vanderbilt in 2015 if he hadn't hurt his elbow. Instead, he saw Dansby Swanson and Carson Fulmer go in the top 10 and ended up sliding to No. 24. He had Tommy John surgery that summer after signing, but was back on the mound less than a year later. In 2017, he put the injury in his rearview mirror, pitching across three levels before getting a big league callup. He's pitching in relief now, but he looks like a frontline starter long-term.
Franklin Perez, RHP, Tigers No. 1/MLB No. 42
Perez jumped on the map pretty firmly in 2016 when, despite not being a full-time pitcher until he was 15, he threw well at age 18 in a 10-start stint in the Midwest League. He shot up lists even faster in 2017 when he reached Double-A as a teenager, all before being the top prospect sent to the Tigers from the Astros in the Justin Verlander trade. There's projection, plus a feel for four pitches here, making it obvious why people are so excited about Perez's future.
Cal Quantrill, RHP, Padres No. 2/MLB No. 39
A bit of a wild card heading into the 2016 Draft, Paul Quantrill's son landed in the top 10 even though he was coming off of Tommy John surgery and didn't pitch for Stanford in his Draft year. The stuff and feel for pitching were legit and he answered any questions about his ability to come back from the injury by reaching Double-A and pitching in the Futures Game in his first full season.
Sixto Sanchez, RHP, Phillies No. 2/MLB No. 48
People were very excited about Sanchez after his United States debut in 2016 when he led the Gulf Coast League in ERA, wanting to see how he would handle his next challenge. All he did was pitch his way from the South Atlantic League up to the Florida State League while not turning 19 until the end of July. A combination of a fastball that has touched triple digits along with outstanding command, not to mention improvement of his breaking ball and changeup, make him the most exciting arm in a Phillies system that has some pitching depth.
Jack Flaherty, RHP, Cardinals No. 3/MLB No. 49 While it might seem like Flaherty had been more of a slow-and-steady climber, he's proven that sometimes that does win the race as he got to the big leagues at age 21 this season. He's always had an extremely good feel for pitching, but with some physical maturation, his stuff has ticked up, giving him the kind of stuff and pitchability that points to a long career in a rotation.
Forrest Whitley, RHP, Astros No. 2/MLB No. 36
It's not often that a first-round pick can be seen as a Draft steal, but the fact the Astros got this 6-foot-7 right-hander No. 17 overall in 2016 could end up being a big bargain. He got promoted twice in his first full season, starting the year in the Class A Midwest League and finishing in the Double-A Texas League before he turned 20. He struck out close to 14 batters per nine along the way and seeing him atop a pitching prospects list a year from now does not sound unreasonable.
Mike Soroka, RHP, Braves No. 4/MLB No. 34
After a strong first full season in the South Atlantic League in 2016, Soroka was already on the prospect map. But when the Braves aggressively double-jumped him to the Double-A Southern League, where he proceeded to finish second in the league in ERA (2.75) while not turning 20 until August, he hit another level completely. He's also thrown close to 300 innings over the last two seasons, showing there's durability to go along with good stuff.
Chance Adams, RHP, Yankees No. 3/MLB No. 55
It might seem strange for a Yankees prospect to fly under the radar, but Adams has done just that for much of his pro career, even after he led the Minors in winning percentage and batting average against in 2016. The upper levels proved to be no more difficult as he pitched his way up to Triple-A and kept hitters to a BAA under .200 for the season. Not bad for a hurler who was primarily a reliever in college.
Triston McKenzie, RHP, Indians No. 2/MLB No. 20
He didn't turn 20 until August, yet he still managed to dominate the Class A Advanced Carolina League. His 186 strikeouts were the second-highest total in the Minor Leagues and he held hitters to a .203 batting average against, going from an intriguing, projectable high school right-hander to a legit frontline starter prospect.
Jon Duplantier, RHP, D-backs No. 2/MLB No. 100
It was hard to know what to expect out of Duplantier as some teams shied away from him in the 2016 Draft because of a shoulder injury that knocked him out as a sophomore at Rice. He more than answered questions about durability by pitching across two levels of A ball and dominating the hitting-friendly California League. He led the Minors with a ridiculous 1.39 ERA and finished third in BAA, making him the choice for MLB Pipeline's Pitching Prospect of the Year honors.
Others of note:
Kolby Allard, LHP, Braves
Adbert Alzolay, RHP, Cubs
Ian Anderson, RHP, Braves
Michel Baez, RHP, Padres
Corbin Burnes, RHP, Brewers
Alec Hansen, RHP, White Sox
Mitch Keller, RHP, Pirates
Adrian Morejon, LHP, Padres
A.J. Puk, LHP, A's
Joey Wentz, LHP, Braves