Any word on where the home US Open Cup matches are to be played for the Sounders?

The round 4 draw for the US Open Cup is this Thursday. If the Sounders get a home match in that round has there been any announcement at to where the game would be on June 6th? I do not know what the turnaround time is for the field in Tacoma but the Rainer's have a home game on the 3rd but then are on the road for a bit and they would have to set up for the S2 game on the 10th at some point so that seems like an option. Driving from Seattle to Tacoma on a Wednesday night is never a fun time, however. I would guess Starfire would be available without checking the actual schedule. CenturyLink is available but they would never play the game there.
Jeremiah had an article in March where he wrote that the new region system the opponents could be the Earthquakes, RSL, Rapids, Reno 1868, Sac Republic, or Col Switchbacks. Reno is playing Sac in round 3 and the Switchbacks are playing San Antonio FC.
There is a chance that the Sounders next three games could be against RSL.