On the field, their ex-teams are huge NFL rivals.

Off the field, brothers Ma'ake Kemoeatu, an ex-Baltimore Raven, and Chris Kemoeatu, an ex-Pittsburgh Steeler, are closer than close. When Chris' pro football career was cut short because he needed a kidney transplant, his older brother, whose organ was good match, quit the Ravens and donated his kidney to his 31-year-old brother.

University of Maryland Medical Center transplant surgeon Dr. Stephen Bartlett said Wednesday that the surgery done Aug. 27 was a great success, and both brothers are on their way to recovery.

"He couldn't play anymore, and I didn't want to be in a position where he couldn't play but I'd keep playing," the 35-year-old former Ravens nose tackle said. "As soon as my brother's health was at risk I wanted to stop everything."

The procedure itself was daunting for the University of Maryland medical staff, as what was an asset on the football field proved to be an obstacle on the operating table.

"When I first met Chris, I said, '385 pounds is a new record,'" Bartlett said. And he said Ma'ake's kidney was one-and-a-half times the size of a normal one. The Ravens listed Ma'ake's weight at 345 pounds when he last played for the team.

"Man, when that thing came out I felt like somebody threw me a small football," he said.

The former Raven said that when the family found out that his brother, who had been suffering from kidney problems since the eighth grade, would need a transplant, he immediately volunteered, quitting the Ravens in 2012.

"I'm the oldest of the seven kids, and it's my responsibility to take care of my younger brothers and sisters," Ma'ake said. "If my younger siblings need blood, it'll be my blood. If they need a kidney, it'll have to be my kidney."

The brothers began preparing for the surgery a year and a half ago. But when the time came, the ex-Steeler called his brother with surprising news: He first needed a coronary bypass. Ma'ake said he comforted his brother in the only way he knew how: with football analogies.

"I knew in my mind that he's fighting a kidney and now he has to have heart surgery," Ma'ake said. "I said to him, it's going to be OK. I talked to him in football aspects. I said, 'all right, we're not going to get this in the first down, but we're fourth and long right now and we have to go deep. We'll make it through the first down_the heart surgery_to the end zone: the kidney transplant."

Chris Kemoeatu called the transplant a "humbling" experience.

"It definitely brought us closer as brothers," offensive lineman of seven seasons said.

The brothers said after they fully recover— which usually takes roughly six weeks— they hope to return to their native Hawaii. Neither brother has any concrete plans to return to football, though both said they received plenty of moral support from their respective teammates in Pittsburgh and Baltimore. The teams are both in the NFL's AFC North Division, and play each other twice during the regular football season.

''Those guys are always asking me, 'did you do the transplant? Did you do the transplant?' The Ravens have always been a big support," Ma'ake said. "I haven't gotten anything from the Steelers yet, but I'm waiting for them to send me something."