Holt has made strides since 2008 in Brooklyn, but still has a significant way to go to become a successful MLB starter. There are still scouts out there who believe he will be best in a bullpen role.
Last year in Brooklyn I saw him 93-95 with his fastball. This year in Binghamton he was sitting at 93, but his location was much improved. Also, his curveball has made major strides. He throws it more, and it has a sharper bite. He's learning how to use it in a variety of counts, when for example, he can throw a get me over offering, or when he can really bury it ahead in the count.
B-Mets Pitching Coach Hector Berrios, who had Holt last year in Brooklyn, claimed that Holt's changeup is his better secondary offering, but Holt only threw a handful in the start I saw him in Binghamton. That day at least, he was clearly more comfortable with his curve. In other starts, he has thrown his changeup more than his curveball. This too, is an important piece of a pitcher's development: learning to work with his arsenal on a given evening.
In his last two starts, Holt has given up nine runs over just 12.1 innings, so he has not yet conquered AA hitters.
Numberically, the most important indicators are there for Holt at AA: roughly a strikeout an inning and a k/bb above three.
Niese's season line above masks the fact that he's really had two different seasons, one from Opening Day -June 1, and one afterwards.
Niese, the Buffalo Bisons Opening Day starter, lasted just two innings, while giving up five runs in his first appearance in a Bisons jersey on April 9. That rocky opening foreshadowed some of the troubles to come in Buffalo and for Niese. When the Mets needed a starter on May 8, they called up Niese who at the time was 0-2 with a 6.55 ERA at Buffalo where the IL was batting .309 against him. Niese lasted two starts in the MLB rotation, firing six good innings against Pittsburgh, but yielding five runs on seven hits in 4.2 innings in his second outing against Atlanta that got him bounced from the starting rotation and back down to Buffalo.
Returned to Buffalo after his two MLB starts, Niese got lit up over his next three outings, giving up a combined 20 runs on 26 hits in 16 innings in three losses. At that point, he, with the help of the Buffalo staff changed.
After his start on June 1, Niese was 0-5 with an 8.05 ERA and an opponents' batting average of .329 in 38 innings. And yet, his peripherals were solid; he was striking out 8.5 batters per nine innings and walking 3.1. The IL owned six homers against Niese.
Since June 1, Niese has been rolling both in AAA and now the big leagues. In his last 56.1 AAA innings, he allowed just seven runs and owned a 0.95 ERA. His strikeout rate was (7.3 K/9 IP), but his walk rate dropped to just 2.1 per nine innings.
What accounts for the split seasons? Niese insists he's doing nothing differently mechanically. However, he acknowledges that he's mixing his pitches more. In addition to relying more on his superior curve, Niese has learned to trust his changeup and cutter, while introducing a two-seam fastball that he uses to produce groundballs. Josh Smolow has done a terrific series here on this site using pitch-fx data to show Niese's development and his increasing reliance on both his two-seam fastball and cutter, and the progress he's made with his four-seamer. You can read his last article here.
Following Niese's strong performance in Houston on Saturday night (7 IP, 4 H, 1 R, 2 BB, 3 K) I'm more optimistic about his big league future than I've been in quite some time.
Mejia has been sidelined since June 23 with a strained middle finger. That's about the only thing that's gone wrong with the 19-year old's season. Striking out over 10 batters per nine innings is no joke, but neither is his groundball rate which has been above 60% at every stop in his professional career. Mejia's doing it with a fastball that lives in the mid-90s, a changeup with nasty sink and a breaking ball that continues to improve.
His next step: getting back on the field.