The biggest man in the Yankees’ clubhouse is feeling tiny.

Even if CC Sabathia was pitching as well as he has in the past the Yankees’ chances of reaching the postseason would be dicey because of a lineup that brings bayonets to a nuclear war. With Sabathia struggling like never before in his Yankees career the prospects of a dark October loom large.

And while Sabathia says he doesn’t bring the putrid performances home with him the large lefty also admits he is letting the entire organization down.

“It’s embarrassing’’ Sabathia said of the recent three-game stretch in which he has been punished. “I feel like if I was pitching like myself we are right in the middle of this thing. The most frustrating thing is that I am letting my teammates down. I am not helping the team win. I put a lot of accountability on myself.’’

Sabathia starts tonight when the Yankees open a three-game interleague series against the Padres at Petco Park. As they began their day off yesterday the Yankees were eight games behind the AL East-leading Red Sox and three games out in the wild-card race.

In his three previous outings Sabathia is 0-2 with an obese 10.93 ERA. He has allowed an alarming 26 hits and seven walks in 14 innings.

Those numbers usually belong to a fifth starter on his way to long relief the minors or the waiver wire not a pitcher making $23 million this year and is owed $76 million from 2014 to the end of 2016. There is a vesting option for $25 million in 2017 with a $5 million buyout.

Of course Sabathia isn’t traveling those roads but with the Yankees’ playoff chances dwindling by the day they need the former ace — Hiroki Kuroda has ascended to that title — to pitch to his pedigree.

Particularly galling to Sabathia was the July 21 start against the Red Sox at Fenway Park when the Yankees staked him to a 3-0 lead after two innings and he gave up four in the third two in the fourth and another in the fifth and vanished.