Patrick Corbin (age 23)
The projection systems appear to give Corbin the best numbers for the upcoming season, and an improvement over the 2012 numbers seems fairly likely. He was somewhat unlucky, with a BABIP of .319 compared to league average of .297, though a higher than usual line-drive percentage may be part of the reason for that. It was good to see a walk-rate from Corbin of only 5.5%, below the mean (8.0%), even in his first major-league stint, though his strikeout rate of 7.2 per nine innings was also lower than the figure of 9.5 put up in Triple-A. We are talking about small sample sizes for both, however.
Corbin is mostly a fastball, change-up, slider guy - the last-named was what he considered his best pitch coming out of college, but he has also been developing a knuckle curve, which he broke out more frequently during his 27.1 inning scoreless streak in 2011. A left-hander like Skaggs, either of them would give Arizona a second left-hander in the rotation alongside Wade Miley: they'd likely be split up, even if they are nominally the #4 and #5 starters. The experience Corbin obtained last year, even if the results were a little uneven, should stand him in good stead for the 2013 campaign.
Randall Delgado (age 23)
[* = when still with Atlanta] Turned 23 on Saturday, and part of what we got back from the Braves for Justin Upton, of course. That might give him a slight advantage, in that for PR purposes, it could be useful to see another one of the pieces beside Martin Prado contributing immediately. - it doesn't seem Nick Ahmed will be doing so in 2013. However, it's very much a double-edged sword, with the downside that, if he is put in the rotation and sucks, the knives will come out. It's worth noting that Delgado was almost traded to the Cubs at the trade deadline last year, for Ryan Dempster, until Dempster used his veto to block the deal.
Delgado has the most major-league experience, but how much success he will have at that level appears to depend largely on whether he can develop a quality third pitch to go along with his fastball and curve - the change-up is still very much a work in progress, by most reports.. If it doesn't come through, we could end up looking at a bullpen arm, which would definitely make the trade look a lot worse. It's also a question of whether Delgago can improve his control, as his walk numbers are definitely too high, both at the major-league level and when coming up in the minors.
Tyler Skaggs (age 21)
The youngest of the three, likely the one with the highest ceiling, having recently been named the top left-handed pitching prospect in the game. However, in terms of translating that to success at the major-league level, 2013 might not be his season, as we saw from the struggles he suffered over the six starts made for the Diamondbacks last year. But he doesn't seem to have much left to prove at the minor-league level, putting up a sub-three ERA at both Double-A and Triple-A in 2012, as a twenty-year-old. As we all know, sub-three ERAs at Reno don't come along often. He and Trevor Bauer at the only to do so, with more than 40 IP, since the franchise moved there in 2009.
According to Baseball America, "The jewel of Skaggs’ repertoire is a sharp 12-to-6 curveball that he throws in the mid-70s. It features late, sharp break and is regarded as one of the best in the minors. He set it up with a fastball that ranges from 89-94 mph and features some armside run. He delivers his heater with good downhill plane and spots it to both sides of the plate. He throws in the low 90s more consistently than he ever has, and he also has improved his fastball command as well. Skaggs’ changeup gives him a potential third plus pitch, but he needs to trust it more. It arrives at 78-80 mph, has some fade and plays well off his fastball."
Pick your pitcher
We've said it before, and we'll say it again: the Diamondbacks are almost certainly not going to get through the season with five pitchers. While you do want your best five starting off the year in the rotation to begin with, it wouldn't surprise me to see all three get starts at some point over 2013. Remember that last year, only two of the original starting five made it all the way through the season: Josh Collmenter was ineffective, Daniel Hudson got hurt and Joe Saunders was traded. The possible return of Hudson makes the situation more messy, but the depth means there should be no need for him to be rushed back.
Picking one is perhaps the major thing left to be decided over Cactus League, and it will be interesting to see how Kirk Gibson and Kevin Towers fit them all in, while also trying to get the front four starters on to their regular schedule. It's probably not something the team wants to drag out too long, for exactly that reason. My instinct is that the alphabetical order above is perhaps also the way in which they should currently be ranked, with Corbin the most likely to claim the fifth spot. But those positions are very much subject to change over the coming seven weeks or so, even if there are no unforeseen road-bumps on the way, in the form of injuries.