#2 To avoid any injury before the match

The face-off between Goldberg and Undertaker was one of the best moments of the blue brand this week. The two men confronted each other but they didn't put their hands on each other. There is no denying a brawl could have hyped the match more as the two legendary Superstars never fought each other in the past.
Considering both Undertaker and Goldberg are over fifty years old, they are in the twilight of their careers. Moreover, the two men are not regular performers anymore. Goldberg's last match was over two years ago, while Undertaker last match was eight months ago. Hence, they might have ring rust and the company wanted to play it safe before the mega clash.
Judging by their age and the time away from the squared circle, an injury could have happened before Super ShowDown. During the last run of Goldberg, the former Universal Champion was busted open a couple of days before Royal Rumble. WWE certainly wanted to avoid a similar scenario on SmackDown Live this week.