I would love to see Lowrie out there full time instead of the anti-clutch GIDP king. But alas, the Sox see Lugo's $9mm contract and can't see fit to bench him. Until Lowrie proves he needs it though, I don't see the point in sending him to the minors. He hits well, and hits in situations where there's need for a hit (see: clutch). He's been a rally starter this whole Texas series, has showed good fielding skills and composure, and his plate discipline is better than the numbers suggest. He has 6 strikeouts in 16 AB, which is certainly not great. But 3 of those are BAD strike calls. Three in a row, in fact, and the only reason Lowrie isn't getting what should be ball 3s and 4s is because he's had 16 major league at bats.
In short: Keep Lowrie. He's better than Lugo already, and has plenty of upside.
Personally, I think we need to get rid of Coco (I hate seeing him in there instead of Ellsbury), send Thurston back down to the minors to work on his batting, and keep Lowry, and Lowell. The final slot should be used for someone like Kielty maybe, who isn't really gonna benefit from time in the minors and doesn't expect to play every day, but doesn't carry trade value like Coco, and can work as an outfielder if he's needed. God knows the guy has been patient with the Sox and their Coco situation.