The Cubs farm system is beginnng to bear fruit. First it was Tyler Colvin, then it was Starlin Castro, and the next one will likely be Jay Jackson.
Jackson is the Cubs best pitching prospect this side of Andrew Cashner and the Cubs have been scouting him in Iowa recently. Jackson carries a 2.41 ERA this year and a 0.94 WHIP built largely on good control - 1.9 BB/9 rate - and pretty good stuff. He's been hard to hit, yielding just 27 hits in 37.1 innings, though some of it has been luck. Jackson's BABIP has been around .200, which is unsustainable. If there is one thing I'd like to see him improve upon is his strikeout rate. His K/9 rate of 5.8 is mediocre, especially considering Jackson has very good stuff. Jackson has a fastball that can touch 95 mph, though he has more success working at 91-93 mph, a mid 80s slider, a curveball, and a changeup. The K rate should improve a bit in a relief role but the Cubs are probably most impressed with that sparkling walk rate - something they haven't gotten from the bullpen as a whole this year. He has already pitched a few games in relief recently in what is, by my speculation, a preparation for his role with the big league club.
You may remember earlier that there was speculation that Andrew Cashner would be called up to try and plug the gaping hole in relief. Instead, they used Carlos Zambrano in the 8th inning role and promoted Cashner to AAA, where he continues to be a starter. I was against bringing him up to Chicago at the time because I was afraid it would interrupt his development. Where once people were concerned Cashner would end up a reliever, this year he's left little doubt that he can be a major league starter, and probably a very good one. So kudos to the Cubs for showing some restraint with Cashner.
So does the same caveat apply with Jackson? I don't think so. Jackson is more polished than Cashner. He's been a starter longer. He has 4 solid pitches that are already major league average or better, and this year he has shown excellent command. It'd be interesting to see which pitch or pitches he eliminates in his relief role. My guess is that since he'd be coming in for an inning or two, he'll got with the hard stuff - the fastball and the slider while occasionally showing the changeup, particularly to lefties. To me, Jackson can pitch in relief, get his feet wet in the majors, then return to a starting role next year without losing as much as Cashner would. He may actually benefit, as relievers turned starters like Pedro Martinez and Johann Santana did (assist to reader Scott on that one)...not that he's at that talent level, but Jackson could be a #3 starter down the road, maybe even a #2 if he can improve his strikeout rate. Another way he benefits is by keeping his innings down. Anytime you can limit a pitchers innings prior to his 25th birthday it increases the odds that he will have a healthy career.
One thing about the Cubs this year, they seem willing to transition from a veteran team to a more youthful, homegrown team, though they are doing it slowly. If Jackson is called up, he will be the 5th homegrown rookie player the Cubs have used this year (Esmailin Caridad, James Russell, Tyler Colvin, and Starlin Castro were the first 4 - Jeff Berg and Jeff Gray were also rookies, though they got their start in other organizations). And it's only May. Players like Andrew Cashner, Darwin Barney, and Robinson Chirinos may not be far behind. The Cubs are rebuilding on the sly. The first phase is bringing in rookies one at a time and mixing them in with veterans. The next phase will be trading some big contract veterans,that is, if the Cubs do indeed fall out of the race by the trade deadline...but that's a subject for next time.