Kenny and Kyle Kobierski grew up in the North Andover Booster Club Youth Football system, which means they learned one important thing: You must beat Masconomet.

"That's just the way it's always been as long as I've been playing," said Kyle Kobierski, a two-way starter at offensive guard and defensive tackle as a junior. "The biggest game every year since fifth grade was Masconomet. You could say there was some hate there."

Well, there is a slight monkey wrench thrown into the Kobierski Thanksgiving Day celebration today, when North Andover High (3-7) hosts Masconomet Regional (7-3) at Walsh Stadium at 10 a.m.

Kenny, the eldest of seven Kobierski children, transferred to Masconomet Regional last December. And he will be wearing the "dreaded" Chieftains uniform and helmet this morning on the Knights home field.

"Yeah, it will be a little weird probably at the beginning," said Kenny, an 18-year-old Masco senior. "But I feel comfortable at Masco. I feel like I belong there. I really like the school. And I especially love playing football there."

Kenny's transfer to Masco was for personal reasons. He struggled at North Andover High for much of his career. And the one place he always found solace, on the football, field never materialized.

"I needed a change. I needed a fresh start. And my grandmother and grandfather live (in Middleton) said I could live with them," said Kenny. "It just happened to be that they lived in the Masconomet school district. So I transferred there."

He was a North Andover High senior when he transferred, but all of his credits didn't go with him. He went to Masco knowing he would have to repeat his senior season.

If he was going to play football this season, Kenny would need Masco to apply for a "fifth-year" waiver with the Massachusetts Interscholastic Athletic Association (MIAA). Because of his age (he turns 19 at graduation) and his story, the MIAA gave him the extra football season.

"We really didn't think it was going to happen," said Masco coach Jim Pugh, "but he had a tough personal story. He had a broken wrist early in his career at North Andover High and he missed a lot of games. We were really thrilled for Kenny when the waiver was granted. He really deserved a second chance. And the best part is, he has made the most of it."

Kenny says his grades have improved dramatically, so much so that college is now an option.

His brother Kyle, at 6-foot and 210 pounds, says he has noticed a change in his brother.

"He's definitely happier than he was here," said Kyle. "The biggest difference is he likes going to school. He'll mention his classes and what he's working on. He's also been telling me I should transfer ... but no way."

Which brings us back to today's games.

Kenny, a 5-foot-10, 170-pound linebacker and cornerback on the 2008 Cape Ann League Large School champs (Masco has clinched the playoff berth and a loss to North Andover would guarantee them a co-championship with Wilmington), will be wearing the white No. 23.

Kyle will be wearing the black No. 59.

"The funny thing is that if he plays linebacker on the side I'm on, I have a responsibility for blocking the outside linebacker. And that would be Kenny," said Kyle. "I'd really like that."

Kenny isn't so keen on hooking horns with his kid brother.

"If we run into each other, we run into each other," said Kenny, "but I won't be looking for him. Personally, I'd rather run into someone else. But if he's there, I'll try to knock him down."

Kyle says that many of his North Andover High teammates still hold a grudge against his brother. And they will be looking to make their voices heard and muscles felt.

"Pretty much everyone wants a piece of him," said Kyle, of his defecting brother. "I can understand. He's playing on the enemy. We don't like Masco around here."

Kenny laughs now that he can see the rivalry from both sides.

"The hate is the same on both sides. It is the same at Masco. They don't like North Andover in anything," said Kenny. "It's a healthy rivalry, though. It's very competitive. Both sides really want to beat the other. I don't have a problem with that."

Kenny said because most of his family lives in North Andover, he believes Kyle will get most, if not all, of the support from his brothers and sisters today.

"(Today) is Kyle's birthday. They should root for him. I don't have a problem with that," he said. "Plus, we still have more games left after this one, maybe one or two games. They can root for me in those games."

The brothers talk a few times a week, In fact, the watched last Sunday's Patriots win over the Miami Dolphins in North Andover.

Kyle said Kenny was indirectly trying to pry information on today's game from him.

"He would ask me about which plays we are running and if the calls are the same as when he played here," said Kyle. "I just shut my mouth and didn't answer. He got nothing out of me. But I give him credit for trying."

The brothers expect to get together on the field after their game, offering each other congratulations. Then they are expected to eat at their grandparents' home in Middleton.

There should be some interesting conversation.

"I'm proud of what Kenny has done," said Kyle, "but I want to beat him on Thanksgiving Day. That is very important to me and North Andover. He will be the enemy (this morning)."