Big Ten rushing leader Tim Spencer of Ohio State signed a four-year contract yesterday with the Chicago Blitz, marking the first signing of a collegiate draft pick by the United States Football League. Said Spencer, a 6-foot-1, 212-pound tailback, "It was not in my best interest to wait for the National Football League draft."

It marked the second such coup for Blitz Coach George Allen, who spirited Tim Wrightman, a consensus all-America tight end from UCLA, from the Chicago Bears' roster last fall. At that time, Allen said he did not anticipate a bidding war with the older, more established NFL. But he changed his tune yesterday, saying, "I didn't get into this (the USFL) to get into a second-rate outfit" . . .

Lawrence Taylor of the New York Giants was named NFL defensive player of the year by The Associated Press. Taylor, who was both the defensive rookie and defensive player of the year for 1981, received 34 of the 84 votes cast by a nationwide panel of sportswriters and broadcasters. Linebacker Ted Hendricks of the Los Angeles Raiders and defensive tackle Randy White of the Dallas Cowboys each got eight votes.

Redskins Coach Joe Gibbs was named the NFC's coach of the year by the Professional Football Writers of America, who also selected kicker Mark Moseley and return man Mike Nelms to their all-NFL team. Tom Flores of the Los Angeles Raiders was named AFC coach of the year.

The San Diego Chargers placed four players, including quarterback Don Fouts and two of his prime targets, wide receiver Wes Chandler and tight end Kellen Winslow, on the team, chosen in a nationwide balloting of 300 sportswriters . . .

Ray Nagel, athletic director at the University of Hawaii, has been named executive vice president of the Los Angeles Rams. Nagel says he will have full responsibility for the operation of the team.

Nagel, 55, a former tailback at UCLA, must find a new field boss to replace Ray Malavasi, fired earlier in the week. Nagel already had arranged for Arizona State University Coach Darryl Rogers to meet with team owner Georgia Frontiere. The club said no offer had been made to Rogers, however, who reportedly is one of several candidates for the vacant head coaching position. Others include current NFL coaches Chuck Knox of Buffalo and Dan Reeves of Denver . . .

Ed Garvey will almost certainly be ousted as executive director at the National Football League Players Association's first team representatives' meeting in March, predicts New Orleans Saints player rep Russell Erxleben. Erxleben said that recent resolutions by some NFL teams urging Garvey's resignation are a solid indication the chief union negotiator has lost the players' support . . .

Bill Walsh, who coached the San Francisco 49ers to their 1982 Super Bowl title, says he and owner Eddie DeBartolo are "looking for the best formula" for another NFL championship--and that may include a new head coach.

The Sacramento Union said in a copyright story that Walsh would keep his general managerial post, but quit coaching. Speculation for a replacement centered on Illinois Coach Mike White, a former 49ers assistant; former University of Southern California coach John Robinson, and Philadelphia Eagles Coach Dick Vermeil.