INDIANAPOLIS — Matt Rhule says he would not be standing alongside other NFL head coaches if not for Tom Coughlin.

So, why didn’t he capitalize on a chance to fill Coughlin’s old shoes?

Rhule was the early favorite to be Giants head coach in 2020. He had an interview scheduled but never made it to East Rutherford because the Panthers acted faster.

A source familiar with Rhule’s thinking told The Post that the Panthers’ show of commitment — flying to meet him and family in Texas as soon as he arrived home from a Mexico vacation rather than waiting for him to visit their facility, and offering a seven-year contract that will allow the patience to make wholesale operational changes — made the difference.

Sure, his nearly $9 million annual salary — far more than the Giants were willing to pay — is a factor, but the source said Rhule could’ve returned to Baylor University for eight years and $56 million. It wasn’t a total money grab.

Rhule was a Giants assistant offensive line coach in 2012 for Coughlin, who was recently fired as a Jaguars executive after the NFL Players Association revealed stories of excessive fines and grievances.

“No man has had more of an impact on me as a coach than Tom Coughlin,” Rhule said. “Sometimes things end a certain way or whatever. Let’s think back about what Tom Coughlin did in Jacksonville, what he did in New York — winning two Super Bowls — and I think he always did it with class and the right way.

“I’m not in anywhere close to this position if I don’t work for Tom. Not just because of the opportunity, but … I learned a lot about running a program. The best coaches at this level don’t sway to and fro based upon the wins. They stay really committed to the way they are going to do things. That’s why you hear me say ‘disciplined.’”

What does Coughlin think of Rhule? Then-Temple athletic director Bill Bradshaw hired Rhule as head coach in 2013.

“Sometimes NFL coaches won’t keep you on the phone. It’s just the token call,” Bradshaw told The Post. “But Tom Coughlin really wanted to impress upon me how important Matt was to the Giants. He said Matt had so much energy and so much enthusiasm that he had Matt talk to the team before they would go out on the field. Tom was very helpful to me in telling me what the pro players thought of him in a very short period of time.”

Rhule, a native New Yorker with family living in the area, has made an impression around the Panthers facility with his 100-words-per-minute speech and multitasking.

The Giants hired Joe Judge within hours of finding out Rhule was headed to the Panthers. Judge’s no-nonsense approach is reminiscent of Coughlin, though Rhule is the true disciple.