In 2012, the Toronto Blue Jays had their eye on Cole Irvin as a high school pitcher. Instead, he headed off to the University of Oregon to pitch for the Ducks. His college career was detoured by Tommy John surgery, which cost him his sophomore season. His return wasn't an instant success. but he eventually returned to form and the Pirates drafted him in 2015, but weren't able to sign him. Finally, when the Phillies took Irvin in the fifth round last year, he was ready to sign and put together a strong first pro season with the Crosscutters.
Irvin was 6-4 with a 3.17 ERA in his red-shirt sophomore season, throwing an impressive 105 innings in 17 games - 15 of which were starts - and striking out 93 hitters on the season. To make things better, he walked just 16 hitters, dropping his walks-per-nine numbers to levels that were even better than his pre-Tommy John surgery numbers.
Irvin came to the Phillies with an impressive change-up that is his best pitch. The pitch well compliments his low-90s fastball. The fastball isn't a great pitch, but when you consider that Irvin has excellent command of the pitch and he has a somewhat deceptive delivery, which makes it a better pitch than the simple velocity would suggest. Considering that his motion and arm speed are the same no matter which pitch he's throwing, and has good speed separation between the two pitches, hitters are left to guess which is coming. Considering that Irvin doesn't often miss the strike zone with either pitch, they better guess right.
Irvin still throws both a curve and slider, but the slider appears to be the one that will be the best pitch for him in the long run. Right now, neither pitch is considered to be overly effective, but at least Irvin has something other than the fastball/change-up combination to use on hitters. If Irvin can make either one of the pitches more effective, than he'll be a much better pitcher long-term. It will also give him a better chance of sticking in the rotation rather than having to move into the bullpen.
Coming out of college, Irvin was a year older than other sophomores, because of the injury, but with a strong first season, he's likely headed to Lakewood in 2017 and his age won't be a big issue. He's completely over the effects of the Tommy John surgery, but that doesn't guarantee he won't have arm problems down the road. Once a pitcher has arm problems, they're always going to be a bit suspect. Of course, if every pitcher who ever had an arm problem was ignored, there would be very few pitchers.
One possible concern would be that Irvin threw just over 150 innings last season between Oregon and Williamsport after throwing just 79 innings in 2015. In 2013 - prior to his injury - Irvin threw just 116 innings, so the workload was a big leap forward, but you have to assume that the Phillies knew what they were doing in having him pitch this past season rather than just shutting him down to preserve the innings.