MLB

Red flags surround powerless A-Rod

The opt-out Alex Rodriguez is long gone. The monster A-Rod who tormented opposing pitchers in 2007 is a thing of the past. This is a new era of A-Rod, the red-flag era.

Rodriguez will get his home runs, he just won’t hit as many. The Yankees and Rodriguez were happy to hear last night that this latest hip injury is only hip flexor tendinitis.

Still, this could just be the tip of the injury iceberg. No one knows for sure.

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Rodriguez is going to have to manage this injury in a new way. He’s going to have to cut down on his workload, and you can be sure that as a result of all that, his home run totals will decrease.

Rodriguez, who is signed through 2017, is sitting on 591 home runs. He is the active leader, but he remains 171 home runs behind Barry Bonds and his 762 homers. Will he be able to catch Bonds?

Earlier in the day Yankees manager Joe Girardi referred to the injury as a “red flag.” How many more red flags will go up between now and 2017? Will his steroid past haunt him in new physical ways? Will his body break down? All these are questions that only time will answer.

Rodriguez stood with his back to the wall in the hallway outside the clubhouse last night after the Yankees beat the Astros, 4-3, at the Stadium. He put on his relieved face and tried to make this out to be only a groin injury. He doesn’t even want to think hip.

“Pretty much for what I feel is my groin, which is connected to my hip flexor,” he explained. “Overall I feel very happy, very relieved.”

He said there is “no relation” between the hip surgery and this injury, that an MRI exam proved that, and there is no thought of a second hip surgery.

He said that back before he had his hip surgery last year, “I thought my performance was going way down, hitting fastballs north of 90 miles per hour and me being very challenged with that.

“I don’t think that’s the case at all right now. I think performance-wise, I know where I need to be. I know where I am.”

Rodriguez knows his swing better than anyone, but here are some numbers that may hint at the decline that could be in his future: In 2007, he led the majors with 54 home runs and a Bonds-like .645 slugging percentage. By June 12 of that season, he already had hit 25 home runs.

This year, Rodriguez has eight home runs and his slugging percentage is .482. Over his last 19 games, he has two home runs in 81 plate appearances. He has grounded into more double plays over that span (three) than he has hit home runs.

What’s really going to have to change for Rodriguez is his workload. Before games, he is always doing extra work and agility drills. All that effort puts tremendous stress on his right side. That hip is the basis for his explosive swing. He generates power by turning that hip and driving his back knee downward.

Last year at this time, Rodriguez had eight home runs, but he didn’t start playing until May 8 because of the hip surgery. In 2008, he produced 10 home runs by June 12, nothing like that amazing 2007 season.

Rodriguez and the Yankees are downplaying this injury.

“The good news to me is that it’s not his labrum … it’s not his hip socket,” Girardi said.

That is good news, but tendinitis has to be managed. There is stiffness in the area, and despite what the Yankees and Rodriguez said last night, there remain questions about the hip.

Rodriguez, who turns 35 next month, will have to learn to deal with it all day-to-day, through 2017.

kevin.kernan@nypost.com