Isabella (back) has been ruled out for Sunday's game against the Raiders, Josh Weinfuss of ESPN.com reports.
Rondale Moore (hamstring) also is out, along with the suspended DeAndre Hopkins, leaving Marquise Brown, A.J. Green and Greg Dortch as the unquestioned top three at WR this weekend. Dortch saw a team-high nine targets in the opener and again should see some looks, but Brown is the downfield threat and de facto No. 1 receiver.