The NCAA agreed Tuesday to settle a class-action head-injury lawsuit by creating a $70 million fund to diagnose thousands of current and former college athletes to determine if they suffered brain trauma playing football, hockey, soccer and other contact sports.

College sports' governing body also agreed to implement a single return-to-play policy spelling out how all teams must treat players who received head blows, according to a Tuesday filing in U.S. District Court in Chicago. Critics have accused the NCAA of giving too much discretion to hundreds of individual schools about when athletes can go back into games, putting them at risk.

Unlike a proposed settlement in a similar lawsuit against the NFL, this deal stops short of setting aside money to pay players who suffered brain trauma. Instead, athletes can sue individually for damages, and the NCAA-funded tests to gauge the extent of neurological injuries could establish grounds for doing that.

Ramogi Huma, president of the National College Players Association, told ESPN's Tom Farrey that the NCPA objects to the settlement because it includes no money for players who have been concussed, forcing them to sue their schools to pay for any treatment related to concussion symptoms.

"There's also no support for players actually suffering from those conditions, from effects of TBI [traumatic brain injury] from that sport," Huma said. "They should have gotten support for players as part of the settlement rather than forcing players to fend for themselves."

Huma told ESPN the settlement also falls short of protecting current players because it does not mandate new return-to-play protocols. Instead, the NCAA and the plaintiffs agreed that remaining guidelines for schools and the implementation of those guidelines are subject to the NCAA's rule-making process.

"And we know what the regular NCAA rule-making process is like. It could take years, or they could shoot it down," Huma said. "The settlement represents yet another refusal of the NCAA to protect players from unnecessary brain trauma. Instead of agreeing to rules that protect players' brains by reducing contact in practices and mandatory return-to-play protocols, such protections would remain optional."

Steve Berman, one of the lead lawyers who cut the deal on behalf of the plaintiffs, described to ESPN how the process will unfold for the 4.2 million players affected by the settlement.

If the judge approves the deal later this year, athletes will receive a notice in the mail telling them: "If you think you have symptoms, fill out a medical questionnaire online that is developed by a team of doctors. You'll have a score. If you score at certain level, that means there's a chance you have a concussion-related injury."

That questionnaire will be designed by a four-person medical science committee that includes NCAA chief medical officer Brian Hainline and noted concussion doctor Robert Cantu. Should players have a score indicating they probably are exhibiting symptoms from a sports-related concussion, they will then have the option of going to a testing center where a specialist can evaluate them -- a $4,000 value -- and, if necessary, recommend further treatment.