OAKLAND -- Entrenched in a Wild Card race with three East Coast teams, the benefit of playing on the West Coast for the A’s is that they usually know how a win or loss will affect their playoff hopes on a given day.

Early on during Monday’s game against the Mariners, the Coliseum’s out-of-town scoreboard was updated to display a loss by the Blue Jays. The stage was set for the A’s to inch closer to grabbing hold of a playoff spot.

It was a golden opportunity that ended up squandered. Sean Manaea dug the A’s into an early deficit, while the offense’s attempt at a late comeback fell short in a 4-2 defeat against Seattle.

• Box score

Snapping a five-game winning streak, the loss keeps Oakland at an even two games back of Toronto for the second American League Wild Card spot with less than two weeks left in the regular season.

• Wild Card standings

“The playoffs are pretty much starting right now,” Manaea said. “We’ve got to do our part. This is going to be a crazy last two weeks.”

Manaea entered the night with a favorable matchup against a Mariners club he’d limited to just one run across 16 innings in two previous starts this season. But a fastball velocity that sat 1.1 mph below his season average resulted in harder contact than he normally allows. Exiting after five innings, the left-hander surrendered four runs on eight hits.

A quick look at Manaea’s strikeout total for the night will tell most of the story about how his outing went. When his sinker is right and at his usual velocity, Manaea is able to rack up the punchouts and swing throughs. On Monday, he recorded only three strikeouts and generated a total of nine whiffs (swing-and-misses) on his 86 pitches thrown.

“Maybe not his best stuff,” manager Bob Melvin said. “The ball wasn’t jumping out of his hand like it normally does, as far as velocity goes. But he battled hard. They made him work hard.

“At the end of the day, he gave up four runs. We just didn’t score enough to support him.”

The other side of the equation was a lack of an answer on offense against Mariners starter Tyler Anderson, who stymied the A’s through seven innings of one-run ball.

A pair of doubles by Chad Pinder and Khris Davis off Anderson to begin the bottom of the third cut the deficit to 3-1 at the time. After that, though, Oakland’s bats mustered just one hit against Anderson the rest of the way and three hits over the final six innings.

The A’s have dropped their last six meetings against the Mariners. Throughout that stretch, offensive deficiencies have been a pattern as they’ve been held to 16 runs over those six games.

“Their bullpen has been really good all year,” Melvin said. “It probably would have served us a little better to put a little more pressure on their starter so we didn’t have to fight against their bullpen the last couple innings.”

The A’s have no choice but to figure out how to break through against Seattle’s pitching staff, or else their 2021 campaign will likely end without a postseason berth for the first time since 2017. With 12 games left in the season, Oakland still has to play six more games against the Mariners. The other six will come against the AL West-leading Astros.

Over the past month, the A’s have developed momentum with solid win streaks only to see it fade by following up with multiple losses in a row. With so little time left in the regular season, they can no longer afford such occurrences.

“We’ve got to find a way to get it done,” Pinder said. “We’re running out of time. We’ve got to get after it tomorrow.”