Seager seemed the odd man out at season's start, but when Mike Carp went down with a sprained shoulder on Opening Day, Chone Figgins moved into his spot at left field and Seager took over at third base.
In the ensuing four games, the left-hander went 7-for-16 with a double and five RBIs, including three straight multi-hit outings.
Counting spring games and Tokyo exhibitions, Seager has hit .400 (20-for-50) with five doubles, a triple, two home runs and nine RBIs in 14 games since March 13.
"He's one of these guys we felt needed to do a lot in the offseason and he did," manager Eric Wedge said. "You look at the way he stands up there with confidence and the way the ball comes off his bat, you really see him maturing as a hitter at the big league level. It's happening right in front of us."