This isn't going to be much of an analysis on Bubba Starling's prospect status. I operate under the assumption that his prospect star status has waned enough to be rather dim. I'd rather analyze why his status is lower; there are probably several reasons, but this article will focus mainly on strikeouts.
Despite league strikeout rates rising to the point where one of every five batters is grabbing some pine (meat), Starling's minor league strikeout rates are still alarming. I'll admit that I haven't been able to catch a Spring Training game yet* or see all the stats**, but Royals Twitter is fond of distributing to the masses notifications of Starling grabbing pine. Scrolling through Twitter is easy, so I've seen my unfair share of Starling strikeout tweets.
*Stupid blackout rules. And also work. And also bees. Honey is nice, though. I like honey.
**Why are ESPN's spring training box scores sometimes formatted like they were created by a 1940s typewriter? Have Spring Training reporting mechanisms not advanced along with the rest of baseball? Do the UX folks at ESPN take Spring Training off and let the number jockeys design things? No need to focus on the user experience and workflow during Spring Training. They're not real games anyway.
Here is the backstory. Bubba Starling...drafted..blah..blah...local kid...blah..blah. His first game action occurred in June 2012, a full year after being drafted. In his first game, Starling struck out three times in six plate appearances. Just a few days later, Starling again struck out three times in six plate appearances. When the Fall season arrived, and it was time to recede into baseball withdrawal, Starling had struck out in 30.2% of his plate appearances. Despite that strikeout rate, in Rookie ball Starling still managed a 135 wRC+ due to prodigious power and a .372 BABIP. Those things didn't last.
The next year, in A ball, Starling struck out in 25.7% of his plate appearances. The power disappeared and the BABIP fell, but he still had a 111 wRC+. His walk rate was good, and he retained a little power. It wasn't enough.
In 2014, Starling got worse. His walk rate fell again, and his strikeout rate went up to 27.3%. His power fell yet again. His BABIP fell yet again. If his stats were rock climbers, they would be the worst ones. They would not be able to scale the practice wall in the sporting goods store. I am only about 65% I could do that, but I was not paid several million dollars to play baseball.
Now then. Starling went to the Arizona Fall League last year. He has some PitchF/X data. If I go to Brooks Baseball, I can actually look at Starling's page, and of course I spent some a little bit of time doing so. Part of my job in real life is to find insight in data. Part of my job as an internet baseball writer is to find insight for you. Sometimes, insight is easy. Sometimes, insight is hard. In this case, it seemed easy.
Keep in mind that these are the smallest of sample sizes against the most variable of competition.
Insight: Starling can't deal with pitches not named "Four Seam Fastball"
Evidence: By way of Brooks Baseball
Insight: Starling can't deal with low pitches
Evidence: By way of Brooks Baseball
Fact: League-wide offense is trending downward
Fact: The strike zone is expanding downward
Fact: Many pitchers focus exclusively on throwing the ball low for ground balls
Fact: Starling has struck out in five of his first seven plate appearances this spring
Hypothesis: Bubba Starling can't deal with low pitches and pitches that aren't four seam fastballs
Unfortunate Hypothesis: Bubba Starling would have the most extreme of strikeout rates if he found himself in the majors this season or any time soon.
Business Intelligence consumers like to use analytics to take action of some kind. They don't like insight for insight's sake. There's an insight here, maybe. It's up to the Royals and Starling to take action.