Reason for Cubs to worry about Baez?

Javier Baez nearly made the Chicago Cubs roster out of Spring Training after putting together an impressive month of March, which included this monstrous home run off of then-Seattle pitcher Randy Wolf.

A middle-infielder with tremendous power and bat speed compared to Gary Sheffield? Yeah, that'll work.

What won't work is the way Baez has played, and acted, in his first week at Triple-A Iowa. Is there reason to worry for the Cubs?