Porter, who de-committed from Washington after Lorenzo Romar was fired and Porter's dad went from there to join Martin's new staff, was a preseason All-America and also preseason player of the year (tied with two others) in the Southeastern Conference.
He reportedly tweaked his hip pregame, started, had two points and two rebounds and was removed, apparently for precautionary reasons.
With Porter out, Kevin Puryear led four Missouri players in double figures with 17 points and also grabbed eight rebounds.
Jordan Barnett scored 15 points, Jeremiah Tilmon had 14 points and seven rebounds, and Kassius Robertson added 11 points for the Tigers in the season opener for both teams.
Missouri was 8-24 last season, 2-16 in the SEC, and was picked in the middle of the pack preseason -- Martin, talking about the rebuild, saying, "I'm not in the business of waiting three or four years."
The Tigers went 10 of 23 from 3-point range and used a 14-2 second-half run to salt the game away.
Nick Weiler-Babb scored 14 points and added five assists and four rebounds, Zoran Talley Jr. contributed 11 points and Lindell Wigginton had 10 points for the Cyclones, who have been to six straight NCAA tournaments but lost four starters from last year's 24-11 team. They were picked to finish ninth in the Big 12.