The NCAA ruled that Tito Horford, a highly sought 7-foot basketball center from the Dominican Republic, and Joe DeLoach, a former national high school record-holder in track, are ineligible to compete at the University of Houston.

Athletic Director Tom Ford said the school will appeal the ruling against Horford. If that appeal is lost, Horford will be released from his national letter-of-intent. He allegedly was visited by an assistant coach during a nonrecruiting trip.

DeLoach was declared ineligible because Olympic gold medalist Carl Lewis made an illegal recruiting visit to DeLoach's home. Only coaches are allowed to recruit. DeLoach has been released from his letter-of-intent.

In an unrelated matter, Houston announced former NBA star Elvin Hayes will return as special assistant to the athletic director, counseling athletes with professional potential on such issues as agents, attorneys and the adjustments from the college to professional level . . .

University of Georgia sophomore Cedric Henderson is academically ineligible for at least the first four games of the 1985-86 basketball season.

After completing summer school, Henderson had not accumulated the 24 credit hours needed to be eligible this fall. He needs 36 hours by winter quarter to be eligible for the rest of the season . . .

Pete Gillen, an assistant basketball coach for five years at Notre Dame, was hired as coach at Xavier, succeeding Bob Staak, who took over at Wake Forest . . .

Eric Chambers, a junior forward for the Mercer University basketball team, died Sunday after collapsing during a pickup game in Elberton, Ga. An autopsy revealed heat stroke as the apparent cause of death.