Monty suddenly in opposing dugout

Until Tuesday afternoon, Jordan Montgomery said he never thought about playing for another team.

“I used to think I’d be a Yankee for life,” Montgomery said.

Instead, he’ll be facing his former team in his first start as a Cardinal when he takes the mound Saturday at Busch Stadium after he was traded for outfielder Harrison Bader shortly before the Tuesday deadline. “It’s awkward,’’ Montgomery said in St. Louis before the Yankees’ 4-3 series-opening loss to the Cardinals on Friday. “It’s strange timing, but it’s a business and I’ll treat it like any other game. … I didn’t want to face them the first time I’m pitching for a new organization, but I’m a competitor and will shake off the nerves.”

General manager Brian Cashman and the Yankees determined the injured Bader and the depth and speed he provides in the outfield outweighed the value Montgomery provided, especially in October.

“If [Cashman] thinks that, I don’t care,’’ Montgomery said. “I’m excited to be wanted. I’m a Cardinal now. I’ll give it my best.”

Montgomery was upset and emotional after learning of the trade, but said his attitude has changed since arriving in St. Louis.

“It’s a good baseball team,’’ Montgomery said. “If I could be somewhere other than New York, it would be here.”

Former Cardinal Matt Carpenter talked to his old teammates about Montgomery, who said that made the transition easier.

“I know the emotions he was going through,’’ said Carpenter, who is making his return to the city where he spent his entire major league career until this season.

“[The trade] happened so fast,’’ Carpenter said. “He played his whole career [in New York]. It’s a great place, a special place and he didn’t really know what to think. And I was trying to fire him up [by saying], ‘It’s hard for you to realize this now, but you’re gonna love this.”

While he pitched well at times in July, the Yankees lost all six of his starts, as Montgomery — as he often was during his Yankees tenure — was a victim of spotty run support. Only Gerrit Cole had made more starts and pitched more innings for the Yankees this season.

But with their eyes already on the postseason, the Yankees determined the possibility of Bader in the outfield was more valuable than Montgomery on the mound.