Theo Epstein knows Ryan Kalish as well as any GM in the minors. Kalish was drafted by the wonderkid in the 9th round of the 2006 draft; one pick before Mark Melancon.
Quick Aside: Look at the 2006 Red Sox draft. It's pretty great. Epstein drafted Justin Masterson, Daniel Bard, Josh Reddick, Brandon Belt (who didn't sign), and Matt LaPorta (who didn't sign). All of those players were at one point Top 50 prospects, and NONE of them were drafted in the first round. Not a ton of impact in this draft, but Epstein can find talent in late rounds.
Kalish was a HS OF/SP/QB/SS/P, so you'd imagine that he'd have some growing pains. Not so; as a 19 year old in the NYPL (A- ball), Kalish hit .368/.471/.540. That was enough to get him on the BA Top 100 (albeit a thanks-for-playing #98 spot). Unfortunately for Kalish, this was the year he also had the Albert Almora hamate bone special surgery. In 2008, he backslid a bit in his promotion to full-season work, though he made it to A+ Lancaster for a dozen games or so. 2009 saw him climb the ladder where he spent the majority of the time in AA, and at 22 Kalish busted into the big leagues; hitting .252/.305/.405 in 53 games. That was pretty impressive, but the 2011 Red Sox had Crawford/Ellsbury/Drew in left, center, and right, respectively. Kalish at this point was considered a pretty decent prospect, but not the caliber prospect as Josh Reddick, who was the 4th OF, so Kalish went to AAA as the outfielder-in-waiting in 2011. Things went quite badly. Things didn't really improve for Kalish in 2012, either; he logges some time with the big league club, but hit .229/.272/.260 there, and was .261/.336/.414 in AAA to boot. That option to Pawtucket came to promote Ryan Sweeney to the club, which is kind of interesting.
2013 was the worst year of Kalish's professional career. He underwent arthroscopic surgery to repair a labrum tear in his right shoulder. That was in January; he'd miss the whole season to this surgery. At this point, Kalish considered retiring. In August, he had ANOTHER surgery, this time cervical fusion surgery. This is identical to the surgery that Peyton Manning had, and capped off another terrible season for him (his 3rd in a row).
Kalish was released by the Sox in December of 2013, and the Cubs picked him up as one of seemingly half-a-dozen 5th OF candidates. Apparently, he's impressed Theo Epstein enough to consider trading Schierholtz away to accommodate him.
Offense
Speed was a sizable part of Kalish's game in the past. He was considered fast enough on the basepaths to steal his fair share of bases, though in the same vein of Albert Almora. Kalish gets anywhere from a 45 to a 55 on his speed, which has diminished slightly as Kalish has filled out. With the increased size has come the body for 12-15 HR; not exactly what you want to see from your RF, but an adequate total from a centerfielder (which Kalish might be able to pass for). Kalish has very good plate discipline, and the projection systems seem to think he'll walk around 8% of the time. He'll also whiff 22%, though. There's an apocryphal story that Kalish didn't swing and miss at a pitch in high school his senior year, but that's not very believable.
We don't have much data on his splits, but it doesn't appear like he was a meaningful platoon split to worry about (Kalish is left-handed). The Lilliputian data we have on Brooks Baseball does tell us, however, that Kalish is a dead-red fastball hitter. He has a .294 average on the hard stuff, and a .181 average on everything else. There just isn't enough data to parse anything too meaningful as to where Kalish's weaknesses are, but it's worth noting that pitchers almost exclusively pitch Kalish away, and they've put him away the same way they put away any left-handed batter with 2 strikes – low and inside.
Defense
Kalish is a solid defender, someone who has always been regarded as a natural baseball player. He's a bit of a tweener now – his arm is fringe-average, and isn't an asset in right, and his speed is average, and isn't an asset in center. He won't embarass himself at either position, but I'd be surprised if he was better than average at center and just slightly above it in right. Kalish had been playing a lot of right field this spring, which is slightly concerning to me. I'm not sure Kalish can cut it offensively to be all that valuable.
Summary
The projection systems give Kalish a line of around .245/.310/.380. That seems fair, and it seems pretty bad for a rightfielder of questionable health. Still, Kalish is an Epstein acolyte, and he looks to get every chance in the world to succeed. It's not the most inconceivable thing in the world to imagine Kalish becoming an average RF, but that seems to be his ceiling. His floor is either perpetually injured (cervical fusion surgery is a hell of a thing) or the lack of development/reps from ages 23-25 will be too much for Kalish to handle. If Kalish can stay healthy, he seems to be a reasonable choice for a 4th or 5th OF, but not much more.
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