If you believe in fWAR, Milwaukee Brewers right-hander Taylor Jungmann is the fourth-best rookie starter in baseball. His 2.2 fWAR ranks behind Anthony DeSclafani (2.9 fWAR) of the Cincinnati Reds, Noah Syndergaard (2.7) of the New York Mets, and Lance McCullers (2.6) of the Houston Astros. Jungmann is just ahead of Minnesota Twins right-hander Trevor May (2.1) and Philadelphia Phillies reliever Ken Giles (1.9).
By more traditional measures Jungmann is having a fine debut of course, with a 3.05 ERA (3.37 FIP) in 106 innings along with a 96/36 K/BB and just 88 hits allowed. It's a very solid season, especially given that the club around him, the 62-81 Brewers, is not exactly a great team.
Jungmann did not have much exposure as a prospect outside of Brewers fandom and his stock moved up and down when he was in the minors. Here's the comment from the 2015 edition of the Baseball Prospect Book, laying out how I viewed him pre-season:
Stereotype Brewers pitching prospect: low-90s sinker, decent slider, fringy-to- average change-up, workhorse build, eats innings. Taylor Jungmann fits that description and should get a major league trial in 2015. A first round pick from the University of Texas in 2011, he’s been brought along slowly but steadily. He made progress with his command last year and showed sharper secondary pitches, resulting in a higher strikeout rate compared to past campaigns. He’s been hovering in the B-/C+ range for some time but his ’14 season was good enough to move back up to Grade B-.
That held up pretty well as far as it goes: his fastball is in the 89-95 range this year, averaging right at 92. The referenced slider is actually more of a curveball, has looked like his best pitch this summer and has more velocity variation than when I saw him in college and the low minors. So far he's been a durable and has held up under a workload.
Fangraphs has taken some close looks at Jungmann lately. Eno Sarris examined Jungmann's sinking fastball and how his use of the pitch varies depending on if runners are on base, referencing this earlier article by Ryan Romano for BP Milwaukee. Tony Blengino at Fangraphs recently delved into Jungmann's batted ball data looking for clues and comes away thinking that Jungmann is pitching at the upper end of his ability and will likely have difficulty maintaining his current success, though Blengino does believe he could be a workable back-end starter.
Detailed analysis of batted ball data is not in my skill set at this time so I don't know if Tony's analysis is the last word from that perspective. I do agree that Jungmann deserves credit for hard work and improvement. Scouts used to worry about his delivery and durability while sabermatricians were concerned about his poor strikeout rates and shaky control at the lower levels of the minors.
That's all improved a great deal and he's stayed healthy. I wouldn't underestimate him.