The Cubs did indeed go for a couple of arms in the supplemental round. One of them, Paul Blackburn, was on my list of potential draftees.
When I was making that list, RHP Pierce Johnson was on the orignal list that I eventually pared down. The reason I took him off wasn't because of his stuff, which is very good, but because he's been somewhat injury prone.
Johnson is 6'3", 180 lbs. and sits in the 92-93 mph range but can get his fastball into the mid 90s. He also features a hard curveball, a cutter, and already has a decent change-up. He also has good command and control. He's a strikeout pitcher who was among the Division 1 leaders a couple of wees ago. If that sounds a bit like he should have been a first rounder, it's because he probably would have been had he not been hurt. Talent-wise some had him in the first round, but a forearm injury scared some teams off. He did come back early, but was rusty and didn't impress. If he's healthy, Johnson is a steal. Keith Law called him a potential # 2 starter, though he isn't wild about his delivery. If his arm is unable to handle a big load, he can still be a power reliever, but the Cubs obviously took him for his potential as a front end starter.
As for Blackburn, this is what I wrote about him earlier...
Blackburn is a bit more polished than Virant, but he does have some projectablity left. He stands 6'2", 180 lbs. and is athletic with a clean delivery. Blackburn features a fastball, curveball, and like most young pitchers, is still working on a change. He throws low 90s now but occasionally hits 94 mph. It's possible he may add a tick or two to that fastball, but what you're looking at with Blackburn is a good all-around pitcher who has a good feel for pitching and the potential for above average stuff, command, and control. Might be a bit safer than some of the others, but he does have upside too. Blackburn feels like a Tim Wilken guy to me.
With the three picks today, we got a sense of the Cubs new drafting philosophy. Both supplemental picks are a bit like Albert Almora in the sense that it's a safe pick with some upside. These players have high ceilings but they also have high floors.