Hisashi Iwakuma is a pending free agent the Mariners could part with and still remain in the race. / Drew McKenzie, Sportspress Northwest

Mariners bosses thought the team was going to win this season. Me too. As did most of the local and national guessers, including Las Vegas bookmakers. Four months later, the guessing has devolved into deciding when to stick in the proverbial fork.

Then they play a game as they did Sunday, coming back from down 4-0 to win 6-5 and fan the tiny flame.

No, I don’t recommend reliance on triple plays and walk-off homers from Franklin Gutierrez as the foundation for a playoff drive. Neither do I recommend that this particular team do much of anything by the non-waiver trade deadline Friday, when the Mariners bosses are forced to join all other teams in decisions about whether to wield the fork.

Teams with records better than the Mariners will trade productive veterans for prospects, signaling that the race is over for them. But the Mariners, 46-54 after Monday night’s 4-3, 10-inning loss to the Arizona Diamondbacks, will be implored by some fans to bust a move because the second wild-card playoff game is only seven games away.

As an experienced fork sticker-inner, I am pleased to offer the Mariners some advice, in the way I would seek Mariners’ counsel if I had a question about marketing bobbleheads:

Put the fork down. Step away from the trade mart. Concentrate on what the franchise does best: Things like the Aug. 8 ceremony for Jamie Moyer, and making mean faces at Sodo neighbor Chris Hansen. Let this roster play it out.

Sure, if a trade partner wants to give up a decent prospect for 34-year-old, free-agent-to-be Hisashi Iwakuma, who has pitched well in his past three games, go ahead. Roenis Elias can be called up from Tacoma to fill the hole in the starting rotation.

Otherwise, it’s just not worth it.

One reason is general manager Jack Zduriencik generally makes poor trades, for which evidence is ample and obvious. But the main reason is what I mentioned at the top: This team was built to win in 2015. When it didn’t, there’s no realistic play left.

In poker, it’s called pot-committed. So many chips are on the table that there is no choice but to play the hand. No folding.

The Mariners are heavy with high-priced veterans who are mostly under-performing, and few prospects who are over-performing. A team approaching the deadline can’t be in a much worse position.

As someone who has borne witness to a cavalcade of bad Mariners teams, I can say with confidence that this is not a bad Mariners team. They lead the major leagues in extra-inning games (two in a row for 14) and in outcomes decided by one or two runs (Monday was the 59th of 100), meaning they are in steady contention.

Consider the last five series were against teams near or better than .500. They split four at home with the Angels, baseball’s hottest team, played three one-run games in New York, losing two, split four at Detroit, and beat Toronto two of three. The Mariners are not a bad team.

Believe me, you hadda be here in the 1970s and 80s to know bad baseball.

But nowhere in the metrics are these guys consistent in any task — starting or relief pitching, offense or defense — that can take pressure off any other aspect. As a consequence, they have a remarkable propensity for spitting up late. They’re wearing themselves out.

Including Monday, the Mariners have lost 17 games in the opponents’ last at-bat, tied for most in MLB.

The combined pressures of failure at the plate, on the mound and on the basepaths fall on what was a strength last year that is now a weakness: The bullpen. Manager Lloyd McClendon last season consistently described the bullpen as the team’s backbone — they had baseball’s best ERA as a group.

This year, absent the backbone, they are spineless. Monday night was another example. Carson Smith, new to closing and overworked, loaded the bases in the 10th inning with two walks and a hit batter. Arizona scored the winning run on a sacrifice fly.

The Mariners may have been close many times, but the volume of work and tension for the pen has compromised this season more than the weak offense.

Zduriencik could attempt to trade for a reliever, but the price will be high for a good one, and no one arm can fix a pen as messed up as the Mariners’, especially absent injured Charlie Furbush.

The GM’s seven-year penchant for big-fly, big-whiff guys like Justin Smoak and Mark Trumbo comes at a cost of filling other needs. The voids add up to a team that is not reasonably repairable from the outside via trade or inside via callup.

To be sellers this week is to signal to fans that the win-now, $120 million payroll team has failed in four months. That assures Zduriencik’s demise. To play it out at least holds the hope that a few more triple plays and a few more home runs from Franklin the Friendly Ghost will provide a rally similar to 20 years ago when the Mariners came back from 13 down in August.

Absent another 100-year miracle, the best the Mariners can hope for this week is to harm themselves no further.