A Cy Young Award candidate two years ago, Hisashi Iwakuma is off to a slow start with a 6.61 ERA. / Drew Sellers, Sportspress Northwest

The Mariners took their 2014 postseason quest to the final day of the regular season before the low-budget Oakland Athletics nudged them out for the second wild card spot. With an offense that ranked among the American League’s dregs, the Mariners reached the playoff precipice mainly because they featured some of the best starting pitching in the majors — and in their own history.

The Mariners led the American League in team ERA at 3.17 while setting club records for the lowest starters ERA at 3.48 and bullpen ERA at 2.59. Among the 15 AL clubs, Seattle also ranked first in fewest runs (554), earned runs (512) and hits allowed (1,240). The Mariners also set a club mark for team WHIP (walks + hits / innings) at 1.173. At 1.182, the starters recorded the third-lowest WHIP in the DH (since 1973) era.

Manager Lloyd McClendon figured on a carry-over this year, but so far production has been horrific. Eliminate Felix Hernandez from the discussion and McClendon is burdened with one of the AL’s worst pitching staffs.

The Mariners rank 15th and last in runs allowed (69) and 12th in ERA (4.65). Deduct Hernandez’s outings, and the Mariners would be tied with the New York Yankees for fewest quality starts in the league with three. As it is, they are only 10th with five.

“Obviously, when you don’t pitch well, that’s a reason to be concerned,” McClendon told MLB.com Monday night after his club staked Hisashi Iwakuma to a 2-0 lead, couldn’t hold it, and lost 7-5 to the Houston Astros when reliever Danny Farquhar allowed two runs in the eighth.

“I’d be lying if I said I wasn’t concerned about it. We’ve got to get it straightened out, because we’re much better than we’ve shown to this point. When you score five runs in a game, you should win a ballgame.”

Without Nelson Cruz’s spree of eight home runs in his past nine games, plus  various contributions from Robinson Cano and Kyle Seager (the heart of the order went 15-for-27, a .555 BA, with 12 RBIs the past two days) the Mariners would be one of baseball’s biggest April flops, especially after all of the World Series predictions.

Iwakuma, third in the Cy Young vote two years ago, has a 6.61 ERA in three starts mainly due to lack of fastball command. James Paxton is at 5.40, also after three, and Taijuan Walker, who pitches Tuesday night opposite Houston’s RHP Collin McHugh, is at 17.18, underscoring again how useless spring training stats are (Walker went 4-0, 0.67).

This is why McClendon has cause for worry: The Mariners are allowing 5.3 runs per game through their first 13 contests. Only one other edition of the club — the 2004 team that lost 99 games — allowed more in April since the occupation of Safeco Field in mid-1999:

Among the club’s listed, only Lou Piniella’s 2000 team reached the postseason. Even Piniella’s 2002 team, his last in Seattle, missed the playoffs despite winning 93 games. The 2007 Mariners ended with a winning record, but finished six games in arrears in the AL West race.

The inability of the starters to go deep into games — Iwakuma has yet to work beyond six innings, Walker hasn’t gone beyond four, and Paxton went 2.2 in his last outing — will  begin to impact the bullpen, as McClendon said Monday.

“This is not going to work for an entire season,” he said. “We need to get consistent starts and more days off for the relievers right now.”

The Mariners enter Tuesday night’s game with a .385 win percentage. They have never made the postseason without an April win percentage of at least .565.