Trying to understand Ryan Adams' lack of playing time

Here is something that is confusing to me: If the Orioles were not planning to play Ryan Adams much at all, why did they call him up from Triple-A? He has played some, but Adams has been on the team for 22 games now and has made just five starts at second base. A caller to my radio show last night said his theory was that Buck Showalter had major concerns about Adams on defense. To me, if that was the case, and I am not saying it is at all, why not just leave him in the minors until his defense improves? Also, Adams has made a few nice plays at second base in the time he has gotten on the field. This is not a blog to criticize or bash Robert Andino in any way. He has been adequate as backup player and done an adequate job with Brian Roberts out. But I don't see Andino as so talented or making such a contribution that Adams has to be seemingly chained to the bench. I would not have expected him to start every game while Roberts is out. But I also didn't expect him to hardly start at all. What is wrong with taking a look at Adams in two or three games a week? Adams has gotten 18 at-bats since his call-up from Triple-A where he was batting .303 with an OPS of .807 in his first season at that level. Now you have to wonder if it will take him a while to knock off all this rust when they send him back to the Tides. Sure, Adams can gain from the major league experience, even if he is not playing much. But if the at-bats were going to be this hard to get, I wonder why the club just didn't callup Brendan Harris or Nick Green to sit the bench and let Adams play regularly and keep progressing at Triple-A. Adams was batting .500, at 18-for-36 this year against left-handed pitching in the minors. But he has gotten just six at-bats (with two hits) against lefties since he's been here. I just don't understand. I hope it doesn't turn out that the Orioles have hindered the progress here of one of their own 24-year-old prospects.