WWE needs to bring as much attention to their shows that they can. They have some big legends that they can call, but they need a reason to show up. Since The Undertaker is taking on Goldberg in Saudi Arabia on June 7th that leaves a perfect opportunity for Taker to make an appearance.
WWE announced during SmackDown Live this week that The Undertaker will be on Raw next week. He will be there to hype his upcoming match against Goldberg at WWE Super ShowDown in Jeddah.
This is a very rare appearance on Raw for The Dead Man. He will likely cut a promo on Goldberg and have a classic entrance. So this should be worth tuning in for.