Commentary from Ross Atkins:

The thinking [with a move to the bullpen] is he has a very impressive arm and is someone who we feel can get major league outs. He showed that in junior high and he should continue to show this in Single-A;  the ability to do that. Travis Fryman told us that his mechanics are perfect and sees him as having the potential to be a high upside bullpen arm now.  We do have some needs throughout the system for bullpen depth, so we are taking a look at Lonnie in that role to see if he could potentially help our major league team on the short term. He is not really intimidated by anybody or anything and should attack guys and come right after them with his fastball.  However, we clearly view Lonnie as having the ability to one day be a corner bat. This is happening because he is more prepared to potentially help in the bullpen now then our other candidates Abner Abreu and Kelvin Diaz, so we are just taking a look at him in that capacity.

Full story here.