NEW YORK — In an alternate reality, perhaps Peter Lambert could rest. He is fighting fatigue while keeping the Houston Astros’ haphazard starting rotation afloat. Lambert labored through five tense frames on Wednesday night at Yankee Stadium, reaching an innings threshold he had not crossed since his age-21 season.Still, there Lambert stood in the sixth. That he even threw a pitch in the frame is cause for celebration. Lambert required 51 pitches to procure his first six outs. A reliever warmed up in the bullpen during both the second and fourth innings, bringing this ballclub’s worst fears close to fruition.“Taking your starter out in the fourth inning, it can wear down on you,” manager Joe Espada said before the game. “We’re trying to navigate those waters. But we’ll find a way.”Keith Law on the Astros' GM firingKeith LawHow is becoming a more impossible question to answer. Twenty-nine games remain in the regular season and the Astros’ pitching staff is in dire straits. A 4.34 ERA since the All-Star break does not suggest as much, but the reliance on a select few arms — most of whom are overworked — has the Astros toeing a dangerous line.Their starting rotation fails to provide length, save for when Lambert starts every fifth or sixth day. Avoiding Tatsuya Imai at any cost and asking closer Josh Hader just to pitch in save situations means that, before the ninth inning, Houston’s bullpen consists of essentially six relievers.One of them is left-hander Steven Okert, who has already made 64 appearances. Only three relievers have logged more. Another is AJ Blubaugh, whose 80 1/3 innings pitched are the most by any of the sport’s 159 qualified relievers.Both remain effective despite their enormous workloads, but for how long is a legitimate question. To preserve both pitchers, Espada must pick the most ideal spots to unleash them. His starting rotation is ruining any such selectivity.Someone has to throw and, too often, it is either a pitcher running on fumes or in the throes of struggles. The latter appeared on Tuesday, when Bennett Sousa and Enyel De Los Santos teamed to surrender six runs across the final two innings of a tied game that became a 9-3 loss. They’ve now combined for a 5.67 ERA in 33 1/3 innings since the All-Star break.Logic may have suggested summoning Okert instead of Sousa to face three left-handed hitters during the seventh inning of a tied game, or to call upon Bryan Abreu, who warmed up while Sousa imploded, in order to limit the damage. Blubaugh had not pitched in two days and loomed as another potential option.