Here's what I've read. He has no patience at the plate. Even though he has great zone recognition, his lack of patience at the plate makes him a contact hitter with very little power. And he seems to have refused to follow instructions to "wait for the right pitch". And we all know how the Rays are with regard to "waiting for the right pitch". In Coach's book, that's a no-no. Tantamount to insubordination.
His ISO was barely above league average (IL) and projections are that he would be a slightly above-average contact hitter with very few walks and fewer HRs (around 5?).
No one seems to be saying that he will be at the ML level another Keppinger. Also, he's stuck between 1B and corner outfield. So as to versatility, there is none.
As to Wrigley, he's still unsigned. It's not like teams jumped at the chance to get him.
Beyond all that, I would have given Anderson an invite to ST. Really, what's to lose? He's not exactly a prospect anymore. Btw, they couldn't be brought up last September. They were not on the 40-man roster.