Hmmm, Griffey, interesting deal.
On one hand, you're making use of you SP depth and dealing for a RP. This is a great idea, as it will allow you to pad your K numbers (and Holds, if your league counts them), while boosting your ERA and WHIP ratios.
That aside, I agree with the other poster. While Lowrie is more valuable than McGehee because of positional depth, they will probably end up with similar numbers- .285-.295 with 20 or so homers. Your problem isn't in the infield. Instead, what you need is a power bat in the outfield. See if you can package Tabata (take advantage of an unsustainable start) with Ogando for Burnett and that OF....if not this team, try another. Burnett will have to keep fighting off Storen, so that's a potential issue, but he'll provide value as a setup guy as well.
Go get some THUMP!
Keep me posted, and good luck!
The Fantasy Baseball King