The Justice Department told the United States Football League yesterday it would not challenge network telecasts of USFL games on Saturday afternoons -- traditionally reserved for college contests -- when the league switches to a fall schedule in 1986.

The league, in a November letter from Commissioner Chet Simmons, had asked the department if a prospective network contract for Saturday games would be challenged under antitrust laws. Current statutory antitrust exemptions for broadcast deals with professional football do not apply to Saturday contests during the college season.

Jim Byrne, a USFL spokesman, said it is not certain the league would play Saturday afternoon games in 1986. Byrne said clearance by the Justice Department was the first step in "very early stages" of looking at Saturday afternoon network telecasts. He said there were "some indications" from an unnamed network that it would be interested.

"It's not proper to comment further on that specifically," he said. Network executives were unavailable for comment.

Currently, ABC and CBS televise college football on Saturday afternoons. In fact, CBS is seriously negotiating with the Atlantic Coast Conference and Eastern independents to join the Big Ten and Pacific-10 conferences on that network for the 1985 season. ABC televised games of the 63-member College Football Association last season; the CFA includes the ACC and the Eastern independents.

NCAA President John Toner, athletic director at the University of Connecticut, was unavailable for comment concerning USFL games on Saturday afternoon.

Randy Hoffman, associate athletic director at Maryland, said, "I don't think anybody will be pleased. We've been fortunate over the years that pro football and college football have not gone heads up against each other. It makes it difficult. But they may be saying, 'We may as well go head to head against college games as pro games.' They probably see it as a weaker market base."

In Washington, J. Paul McGrath, assistant attorney general in charge of the antitrust division, replied that under the terms outlined by Simmons, the government "has no present intention to institute enforcement proceedings challenging" the proposed broadcasts.

The terms include a guarantee that no network games would be blacked out to the home audience, and that only one game would be broadcast nationally on any given Saturday afternoon. A network could carry up to four games regionally, however.

All other USFL games would be played on Saturday nights or on other days, under the league's proposal. The league already has a deal with a cable outlet, ESPN, to carry night games. Another prospective agreement would be for ESPN to carry Sunday contests.

The league did not specify a particular network for the Saturday afternoon package. ABC has carried USFL games in the past.

The league began play in the spring of 1983, sticking to the spring-summer format again last year and in its 1985 schedule. It said USFL teams lost an average of $3.5 million last year, and hopes a switch to a fall schedule and a more attractive television package will reverse those losses. Television revenues totaled only $1.3 million per team last year, compared to $14 million per team in the National Football League.