With one out, Healy singled on a popup into right field. David Freitas followed with an infield single between third and short, with Healy advancing to second base.
Heredia got the winning hit on a 2-2 pitch from Alex Claudio (1-2), the sixth Rangers pitcher.
Erik Goeddel (2-0), the seventh Seattle pitcher, worked two scoreless innings for the victory.
The back-and-forth game saw the Mariners blow a 6-3 lead before rallying in the eighth inning, only see the Rangers tie it again.
The Rangers evened the score at 8-8 in the ninth against Mariners closer Edwin Diaz.
Jurickson Profar lined a single to left and moved to second on a wild pitch. Nomar Mazara popped out to third before Joey Gallo hit a grounder to first baseman Healy. Diaz covered the bag and recorded the out, but Profar scored all the way from second when the pitcher mishandled the ball. Mariners manager Scott Servais was ejected while arguing for interference.
Jean Segura's third hit of the game brought home Gordon Beckham with the go-ahead run in the bottom of the eighth.
The Rangers broke a 6-6 tie in the top of the eighth against reliever Juan Nicasio.
Mitch Haniger also had three hits for Seattle, and Healy belted his eighth home run of the year.
Mariners designated hitter Nelson Cruz left the game shortly after being hit on the foot with a Brandon Mann pitch in the fourth inning. X-rays were negative, and Cruz was diagnosed with a bruised right foot.
Robinson Chirinos had three hits and three RBIs for Texas, and Gallo hit his 13th homer of the season.
Seattle starter Mike Leake allowed six runs (five earned) on nine hits in 5 1/3 innings. Texas starter Mike Minor yielded six runs on eight hits in 3 1/3 innings.
The win provided a bit of good news to end a rough day for the Mariners. Earlier Tuesday, second baseman Robinson Cano accepted an 80-game drug suspension from Major League Baseball after testing positive for a diuretic that can be used as a masking agent.
Cano already was sidelined due to a broken bone in his right hand sustained Sunday, and his time on the disabled list will count toward the suspension. His replacement at second base, Beckham, went 2-for-4.
--Field Level Media
Texas | Seattle | |
Mike Minor | Player | Mike Leake |
No Decision | W/L | No Decision |
3.1 | IP | 5.1 |
5 | Strikeouts | 2 |
8 | Hits | 9 |
16.20 | ERA | 8.44 |
Texas | Seattle | |
Robinson Chirinos | Player | Mitch Haniger |
3 | Hits | 3 |
3 | RBI | 2 |
0 | HR | 0 |
3 | TB | 5 |
.750 | Avg | .600 |