Motter's three-run homer capped a five-run sixth inning that broke the game open in Seattle's 5-0 victory over the Rangers on Saturday night.
It was the second homer of the season for Motter, hitting .333. Along with four doubles, all six of his hits have been for extra bases.
"It's always nice when you get that opportunity, but I'm just hoping for Segura to get back here real soon," said Motter, who was acquired in an offseason trade with Tampa Bay.
Motter's two-homer start matches his total last season as a rookie with the Rays, where he hit .188 in 33 games with three doubles and nine RBIs.
"He's been OK out there," Mariners manager Scott Servais said. "Taylor has a lot of energy and we've needed it. He's gotten some big hits. The power he's hitting with and really driving the ball, it's been great. He jumped on a breaking ball up in the zone, a big hit tonight."
In a three-year stretch, Motter hit 16 homers at Double-A Montgomery in 2014, followed by 14 and 13 homer seasons at Triple-A Durham.
The versatile Motter, who played seven defensive positions in the Minor Leagues, was hard-pressed to recall a similar hot streak at the plate.
"That's a good question. In 2015, I felt pretty good, so maybe 2015, but this has been a heck of a run so far," he said.
Servais said Motter's taking a controlled approach at the plate so far this season.
"He's in good hitting position and he's not trying to jump out to get the fastball," Servais said. "He's under control and he's on time. His foot's down, his hands are back on time so he can handle the breaking ball when it's a good spot for him. He's not getting cheated. He's putting a good swing on it and the ball is jumping off his bat pretty good."
Jim Hoehn is a contributor to MLB.com based in Seattle.