The Rockies won Saturday's game, 2-1.
Morales struck out five batters and walked five. Young recorded two strikeouts.
"He still has enough stuff where he can get out of traffic and strike some guys out, but he didn't have his great command today," Rockies manager Walt Weiss said of Morales.
The pitching matchup took center stage, but there was also noteworthy action in the batter's box.
Seattle's Corey Hart, playing in his first Cactus League game since March 20 due to a sore forearm, went 0-for-3. He finished Cactus League play with a batting average of .132. By contrast, Robinson Cano also went hitless in his two at-bats Saturday, but still managed to finish spring by hitting .412.
Charlie Blackmon had two hits in three at-bats for the Rockies.
New Mariners manager Lloyd McClendon was pleased with what his club accomplished this spring as they put together an 18-12-3 record.
"Spring Training is Spring Training. You always have to temper your excitement a little bit," McClendon said. "But I was very pleased with the work we put in and the cohesiveness of this club -- their competitive spirit. I think they're clicking on all cylinders and are ready to go."
The Mariners will open the season Monday against the Angels in Anaheim. The Rockies will travel to Miami on Sunday before starting the season the next day against the Marlins.
Up next: The Mariners open their regular season on Monday in Anaheim with Felix Hernandez making his club-record seventh Opening Day start. First pitch will be at 7:12 p.m. PT and the game will be televised by ESPN2 and ROOT Sports and also be available to MLB.TV subscribers. The Mariners have won a franchise-record seven straight openers. The last Major League team to win eight straight or more Opening Day games was the Reds with a nine-game streak from 1983-91. Hernandez has much to do with that streak as he's 4-0 with a 1.33 ERA in six Opening Day outings.
Jesse Sanchez is a national reporter for MLB.com. Follow him on Twitter @JesseSanchezMLB. This story was not subject to the approval of Major League Baseball or its clubs.