Nevertheless, he's anticipating changes in the way injuries not affecting the head are evaluated on the sideline.
Goodell was in Denver for Saturday's Ravens-Broncos playoff game.
Griffin had reconstructive ACL surgery Wednesday after reinjuring his right knee in last Sunday's playoff loss to Seattle. He also strained a ligament in the knee last month against Baltimore.
That raised questions whether Redskins coach Mike Shanahan should have let Griffin in either game after it was clear the quarterback was hurt.
Goodell said it was a "medical decision" and noted Griffin had no problem with it, either.
"Now, people can argue whether it was the wrong decision, but it was a medical decision and that's what we want it to be," Goodell said.
"Will we make further changes? Yeah, I would anticipate we will. We'll always look at that and try to see what else we can do to make sure the proper medical attention is being given, that they make the best medical evaluation and it's their determination to make."
Asked if independent doctors were needed on the sideline, not those chosen by the team, Goodell insisted the physicians were impartial.
"When you say independent, all these doctors work for other institutions," he said. "And they're well-respected and the medical care in the NFL is outstanding. And if they have a concussion, they have to see an independent neurologist before they're cleared to play."
He noted that Dr. James Andrews is a highly regarded orthopedic surgeon, "and I think he made a judgment and the team made a judgment, and Robert Griffin seems to be comfortable with it, too. I think as long as they are medical decisions, that is our primary objective."
Goodell said the league is looking into the poor playing conditions at FedEx Field last weekend, when not only was RG III hurt, but the Seahawks lost their best pass rusher, Chris Clemons, to a torn ACL in his left knee.
"We're going to evaluate that," Goodell said. "Interestingly enough, we had no complaints of the field in the Dallas game (the week before). And so what we have to do is think through that a little bit and say what happened between there, and our staff is looking at that to try to determine should a field be required to be re-sodded, even between the hash marks."
In a meeting with reporters following a fan forum at Sports Authority Field, Goodell also addressed the recent findings that Junior Seau had a degenerative brain disease often linked with repeated blows to the head when he shot himself in the chest last year.
Researchers from the National Institutes of Health said Thursday the former NFL star's abnormalities are consistent with chronic traumatic encephalopathy, or CTE.
Goodell said the findings underscore the need for additional research into CTE and he noted that NFL teams have given a $30 million research grant to the NIH and are committed to spending $70 million more on heath research, as specified in its collective bargaining agreement with the players.
"It's why we're investing in the research is to find out more about it, CTE, in particular, but also brain injury and brain disease. And we need to have a lot more research because there's still unfortunately a lot of unknowns," Goodell said.
The hard-hitting linebacker played for 20 seasons with San Diego, Miami and New England before retiring in 2009. He died at age 43 of a self-inflicted gunshot in May, and his family requested the analysis of his brain.
Seau joins a list of several dozen football players who were found to have CTE. Boston University's center for study of the disease reported last month that 34 former pro players and nine who played only college football suffered from CTE.
The NFL faces lawsuits by thousands of former players who say the league withheld information on the harmful effects of concussions. According to an AP review of 175 lawsuits, 3,818 players have sued. At least 26 Hall of Famer members are among the players who have done so.
Goodell noted that his top priority as commissioner is to reduce head trauma in the game.
"We haven't waited for the research. We've been making changes for the game, making rule changes, making equipment changes," he said. "Medicine has a ways to go. We need to fund more research. We have that in our collective bargaining agreement, to have $100 million worth of research. We've funded $30 million to the NIH last fall, so that research is under way and I think that will be beneficial in treatment and also in what we can do in continuing to make not just football safer but every other sport."
On other topics, Goodell said:
• He hasn't made a decision on when to reinstate New Orleans Saints coach Sean Peyton, who was suspended last season because of the team's bounty scandal.
• He hasn't made up his mind on where he stands on the expansion of playoffs but wants to make sure any change in the format wouldn't dilute the importance of the regular-season games.