In the aftermath of the brawl between Rajon Rondo and Kris Humphries, Celtics guard Courtney Lee claimed the Nets “threw the first punch” during the C’s fourth home loss in eight tries this season. He was speaking figuratively, of course, but the Celtics suffered — literally.

Lee (elbow) and Jeff Green (knee) both left the game with injuries, and each returned in the fourth quarter.

“I’m fine,” said Lee, who had no ice on his left elbow as he talked to reporters after the loss. “I’m fine. It was my elbow. My whole arm was stinging, so I didn’t know what was hurt, but after awhile, it wore off and I was fine.”

Meanwhile, Green limped through the locker room — his sprained right knee wrapped in a protective bandage. Celtics coach Doc Rivers told The Dennis & Callahan Morning Show he “didn’t think” Green was hurt, and team personnel confirmed Green’s return to action indicated nothing serious, but he’ll be re-evaluated Thursday.

Green and Lee escaped without serious bodily injury, but their egos may not have. While Rivers didn’t call them out by name, he cited only veterans Rondo, Kevin Garnett, Paul Pierce and Jason Terry as those Celtics who “understand the jersey they’re wearing and the pride.” The others? “It’s almost like they think because they put the jersey on that they are something. You’ve got to earn it here.”

Well, outside of the four players Rivers named Thursday morning, Green and Lee have logged more minutes than any of the other new faces on this roster, and neither has proven himself in a Celtics uniform.

As Grantland’s Zach Lowe noted, Green’s 8.34 player efficiency rating matches his $8.3 million annual salary. Unfortunately, among forwards who log 20 minutes a night and have played at least 10 of their team’s 13-16 games, that number ranks third from the bottom of a list that includes 72 names.

Asked if he’s disappointed in Green, Rivers said, “”I am. I think he’s better, and I think he can be better.”

And Lee’s been worse. Among guards who average 20 minutes a night and have played at least 10 games, his 7.01 PER ranks second from the bottom of a list that features 76 names. Only Austin Rivers has been worse, and Doc knows all about his son’s NBA growing pains. Only Lee is a veteran making $5 million a season.

While neither Green nor Lee may be seriously injured, the way they’re playing, both are hurting the Celtics.