All three of the players had been with Triple-A Tacoma, which was eliminated from the Pacific Coast League playoffs on Saturday night by Sacramento.
Moore, regarded as the best all-around catcher in the farm system, split the season between Tacoma and Double-A West Tennessee. In 91 games with the Rainiers, he hit .294 with nine home runs and drove in 43 runs.
A sixth-round Draft choice in 2006 out of the University of Texas-Arlington, he was recently selected as the Rainiers' Player of the Year.
To make room on the 40-man roster for Moore, the Mariners released right-hander Stephen Kahn.
Kahn has been hurt each of the past three seasons and has not pitched during the regular season since 2006. He was sidelined this season with right shoulder inflammation, and missed '07 and '08 with a pair of knee injuries.
Tuiasosopo, 23, will be in his second stint with the Mariners this season. He made the Mariners' 25-man roster out of Spring Training but did not appear in a game. He underwent right elbow surgery in April, but came back and hit .261 with 11 home runs and 35 RBIs in 59 games for the Rainiers. In four playoff games, he batted .313 (5-for-16) with one home run and four RBIs.
Olson has pitched in 24 games with the Mariners this season, including 11 starts. He is 3-5 with a 5.88 ERA in 75 innings, with 45 strikeouts and 32 walks. In nine starts with Tacoma, Olson went 2-3 with a 4.94 ERA and notched the Rainiers' only playoff win.
Jim Street is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.