The Mariners will make another roster move prior to Sunday's game in Minnesota, which would have been Maurer's next start. They could use reliever Hector Noesi to fill that role as he's already on the roster, but most likely will promote right-hander Jeremy Bonderman from Tacoma.
Manager Eric Wedge said a decision has been made on who'll start Sunday, but the team isn't ready to announce it yet.
Bonderman was pulled from his Tuesday start for the Rainiers after allowing one run on five hits in four innings. The 30-year-old veteran is 2-4 with a 4.52 ERA in 11 starts with Tacoma and has an opt-out date on his Minor League contract approaching at the end of the month.
Liddi, 24, was batting .267 with nine home runs and 37 RBIs in 50 games for Tacoma. He provides some roster relief at first base, third base or in the outfield for a Mariners club that is temporarily without first baseman Justin Smoak and outfielder/first baseman Michael Morse due to minor injuries.
Neither Smoak nor Morse is on the disabled list, but Morse remained behind in Seattle due to a strained quadriceps, while Smoak is scheduled to take batting practice Wednesday for the first time since feeling tightness in his right oblique muscle last Saturday.
Liddi played 53 games for Seattle in 2011-12, batting .224 with six home runs and 16 RBIs in 53 games. The native of Sanremo, Italy, is the first Italian born and raised player to play in the Majors.
"It's always nice to be back in the big leagues," Liddi said. "That's where you want to be, so it's nice be back here."
Wedge said Maurer just needs time to develop his game at Triple-A, a level he skipped this season in going straight to the rotation out of Double-A Jackson.
"The biggest thing is just staying consistent with his tempo and mindset and approach over the course of the game," Wedge said. "[Tuesday] was a good example. He starts out good, then things start to happen and he tries to do a little bit more. That's when you lose release point and command and that's where he gets into trouble.
"It's not that his pitches weren't doing what they need to do. His stuff is legit. He's going to be a big league pitcher for a long time. But he just has to get himself in the right position to execute pitches consistently throughout the course of a game."