Seager jumped on a first-pitch slider from Friedrich and drove it into the right-field seats for a two-run shot in the Mariners' 4-2 loss. It was his 24th homer, with half of those coming against left-handers.
That's an extraordinary feat for the 27-year-old third baseman, who has the most home runs in the Majors by a left-handed hitter off southpaws.
"I think he's come so far in that department," manager Lloyd McClendon said. "He takes a lot of pride in it. They keep throwing them at him and I think he leads the league in home runs off left-handers.