As noted earlier, WWE has quietly moved Andrade and Zelina Vega back to the SmackDown roster after they were moved to RAW in the 2019 Superstar Shakeup last week. Aleister Black, who is married to Vega, was also moved to the blue brand after being confirmed for the red brand in the Shakeup last week.
Besides WWE United States Champion Samoa Joe going to RAW from SmackDown on tonight's show, there will be at least one more roster change as Cesaro is moving from SmackDown to RAW, according to John Pollock. This would break up The Bar as Sheamus is staying on SmackDown. As noted, the tag team of Ricochet and Black is also splitting up as Ricochet will stay on the red brand. Pollock adds that Cesaro is scheduled for tonight's RAW in Des Moines, Iowa.
Regarding Andrade and Vega moving back to SmackDown, PWInsider reports that the move was made, in part, at the request of Fox officials as they prepare for SmackDown to join the network in early October on Friday nights. The network apparently felt like the blue brand lacked any major Latino Superstars following the Superstar Shakeup as Rey Mysterio was moved to RAW. Fox has plans to spotlight WWE's Latino talents on their Spanish language channel, Fox Deportes, later this year when the Friday night move happens.
Black's move to SmackDown was, at least in part, due to his marriage to Vega. WWE has made an effort to keep married couples on the same brand. As noted, Andrade will be back on the same brand as girlfriend Charlotte Flair now. PWInsider adds that there were some ideas pitched for Black on SmackDown that went with the move.