The Mets signed the 6-foot, 185-pound Montero, and in 2011, he pitched at four classifications in the Mets' Minor League system. That's almost unheard of, but he was stellar at every level.
Montero began his career in May that year on the Mets' Dominican Summer League team, pitching and starting in four games. He threw 18 innings and had a great 1.00 ERA and a 0.38 WHIP when he was assigned stateside to the Gulf Coast League Rookie-level club at the end of May. Montero pitched there until August 2, and put up a 1.45 ERA and 1.09 WHIP. He started four games of the seven in which he appeared. His ERA was 1.45 and his WHIP was great, once again, at 1.09. On August 8, the Mets assigned Montero to Kingsport in the Rookie-level Appalachian League. For the first time, Montero scuffled a bit. His ERA increased to 4.24 and his WHIP went up to 1.35, both highs for his young career. However, Montero threw only 17 innings before being sent to Class A Short-Season Brooklyn for two games to finish the season. Altogether, in his rookie year, he pitched 71 innings and finished the year with a 2.15 ERA and a 0.95 WHIP. Outstanding.
Success continued the following year as Montero pitched for Class A Savannah and Class A Advanced St. Lucie at the age of 21. Last year, he was promoted again. Montero pitched at Double-A Binghamton and finished at Triple-A Las Vegas.
This May, after only three years and having pitched at every classification, Montero was pitching in the Major Leagues, having taken a role in the rotation following an injury to rookie Jacob deGrom. He made his debut on May 14. It's an aggressive progression, but one the determined Montero earned with excellent pitching results in the Minor Leagues. With deGrom's return from injury, Montero is back at Triple-A Las Vegas. His strong performance in the beginning of his career has earned him the No. 6 position on the Mets' Top 20 Prospects list.
Montero has a full repertoire of pitches that include a 93 mph fastball, a 92 mph sinker, an 87 mph changeup and a slider that sits between 81 and 82 mph. He can bring his fastball to 94 or 95 when needed.
In the Minor Leagues, Montero found success with outstanding control of his entire arsenal. In his career before his promotion to the Mets, he had yielded 100 walks in 428 1/3 innings. That's a tad above two per nine innings. Montero had struck out over eight batters per nine.
Major League hitters walked more often than in Montero's past and were making more frequent and fairly loud contact off him in his brief stint with the big league club. That's to be expected. He will ultimately become familiar with the difference between Major League and Minor League hitters. The difference is huge. Combined in his seven starts, Montero yielded more home runs in his short time at the Major League level than he had in any entire Minor League season in the past. As has been the case in his career so far, Montero was hit harder by left-handed hitters than righties.
Montero's return to the Minor League system for further development should especially help his secondary pitches. He has a strong arm and good enough pitching mechanics to work out any issues uncovered in his initial exposure to the Major Leagues. If Montero keeps the ball down and trusts his stuff, I believe he will emerge as a long-term back-end-of-the-rotation starter.