WWE SmackDown is scheduled to go to Friday nights on Fox beginning October 19, 2019, but it looks like there could be more WWE programming on the Fox networks.
There is said to be a very good chance that FS1 will air a SmackDown pre-show each Friday night, according to Richard Deitsch of The Athletic. There's also talk of FS1 hosting post-shows following major WWE pay-per-view events, such as SummerSlam.
Regarding on-air talents for the potential WWE pre-shows and post-shows on FS1, Deitsch noted that the talents would be hired by Fox but there would likely be some kind of approval from WWE.
It was reported earlier this summer that there was talk of doing a weekly WWE studio show on FS1, perhaps on Wednesday nights.