(This happened a couple of weeks ago, sorry for the delay.)

Since the Force lost their shortstop (Chelsea Spencer) to the Thunder earlier this month, they were in need of a replacement. And since the Thunder now had a SS to spare, off she went to Philadelphia.

The actual reason given is that Rendon (now LaFountain) recently got married, and she wanted to move closer to her new husband (Jason "J.T." LaFountain).

Here is the Force story.

Here is the Thunder story.