If you're a team that is contending for a playoff spot - and I assume this team wants to be in that position every year for the conceivable future - you do not trade away major league talent to restock a farm system.
And they're not filling 8 positions, they're helping to fill the 13-14 spots generally reserved for position players on the 25-man roster. Out of the players you listed, LaRoche, Zimmerman, Werth, Morse, and Flores have missed time with significant injuries. Why would you eliminate the depth and possibly sacrifice a playoff run to fill your minor league system with some C+ prospects?
I generally agree with that. Here is the issue though. When Jayson Werth gets back, we will have Werth, Harper, Morse, Moore, and LaRoche to fill 4 positions (the OF and 1B). Each of those guys should be every day players. However we have a gaping hole in the lineup at 2B unless you want to platoon. Regardless, you have talent that will be sitting on the bench unused. Why not use that to either help solidify the future or try to go get a legitimate bat to play 2B. LaRoche's contract is up after this year and Morse's contract is up after next year. Doesn't it make sense to get something for these guys while we can if they can't all make major contributions to a pennant race?
EDIT: This all becomes moot if Moore stops hitting but I believe he will keep it up.
