MLB

Aching Andy’s start vs. Angels crucial for Yanks

DANDY OR NOT? Andy Pettitte, who skipped his scheduled start Wednesday after experiencing discomfort in his left elbow in his previous start, will go against the Angels on Monday after a successful bullpen session yesterday. AP

SEATTLE — Andy Pettitte won’t know until Monday against the Angels whether or not he is beyond the problem that forced him to miss a start last week.

Pettitte threw a regular bullpen session before last night’s Yankees-Mariners game at Safeco Field and said everything went well. What the veteran left-hander didn’t say was that he knows for sure the shoulder is free of the tiredness it experienced during his last start, Sept. 11 at home against the Orioles. He may have to wait until he faces the Angels, hoping his left shoulder doesn’t leak strength.

“I will find out Monday,” Pettitte said. “Get through that start and I will know. Obviously, [yesterday] was a long bullpen and there was no problem.”

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Pettitte said he does not believe how he feels today will tell him anything he already doesn’t know about his shoulder, which bothered him late last year but had been problem-free this season until that Sept. 11 outing.

To say the Yankees are nervous about what they will find out Monday night in Anaheim, Calif., would be an understatement. A healthy Pettitte is a must for the Yankees to win in the playoffs, which likely will open with the Yankees, as the AL East champ, facing the AL Central champs, in the best-of-five ALDS.

The Yankees opened play last night leading the East by 6½ games over the Red Sox, who beat the Orioles, 3-1. The Tigers, clinging to the AL Central lead, were three lengths ahead of the Twins after a 3-0 loss at Minnesota.

As good as Yankees ace CC Sabathia has been this year, he is 2-3 with a 7.92 ERA in five career postseason starts for the Indians and Brewers. A.J. Burnett, last night’s starter, was 1-5 with a 6.14 ERA in his previous nine starts and had allowed 60 hits and 24 walks in his last 55 2/3 innings. Burnett has never appeared in the postseason. Nor has Joba Chamberlain, who will start tomorrow.

That’s why it’s imperative that the 37-year-old Pettitte, who has a postseason record of 14-9 with a 3.96 ERA in 35 playoff starts, be healthy and pitching effectively next month.

“I have had a good period of rest,” said Pettitte, who is 13-6 with a 4.14 ERA in 29 starts this year and pitching better in the second half. “I want to get to Monday without it fatiguing out.”

One positive Pettitte and the Yankees took from yesterday is that his wing didn’t bark.

“I felt so good I had to cut it back,” Pettitte said of the bullpen session.

Because the shoulder started to bark midway through his Sept. 11 start, Pettitte will be curious how it feels around the fourth inning Monday.

“That’s when it started to ache,” said Pettitte, who went five innings, gave up three runs and five hits and walked three Orioles in his last start.

He was slated to start Wednesday against the Blue Jays, but skipped his turn.

“I have been feeling good and I hope to get back in rhythm with all my pitches,” said Pettitte, who could be manager Joe Girardi’s choice as the No. 2 or 3 starter in the first round. “We have not wrapped anything up. We have a tough stretch ahead.”

One that will get more difficult if Pettitte experiences a problem Monday.

Depending on what ALDS schedule, which the team with the best record gets to choose, they may require only three starters in the first round because one schedule features an extra day off. If Pettitte can’t go, Chamberlain could be the third starter behind Sabathia and Burnett.

After that, however, the other options are Chad Gaudin, who could be valuable as a reliever, or the struggling Sergio Mitre.

And those are options the Yankees don’t want to consider.

george.king@nypost.com