Representatives of the Arizona franchise in the new United States Football League said yesterday they will challenge the Chicago Blitz's signing of former Arizona State offensive guard Bruce Branch.

"We consider him to be our player," said the Arizona team's vice president, John Chaffetz. "We plan to take this to the league commissioner, Chet Simmons, and ask him to look into it. This may take some time to resolve."

Chicago owner Dr. Ted Diethrich, a Phoenix surgeon, denied there were any violations involved with the Branch signing and said his team had received the approval of Simmons at the league meetings this week in Washington, D.C.

Branch, a 6-foot-4, 255-pound senior, was declared academically ineligible by the university last month -- essentially ending his collegiate career. He sat out the 1979 season because of grade problems and was in his fifth and final year of athletic eligibility at Arizona State . . .

Detroit running back Billy Sims said he will continue his holdout unless he is allowed to have a face-to-face meeting with Lions owner William Clay Ford.

Sims, who has broken many of the Lions' rushing records, although he has only been in the National Football League two years, was escorted to a crowded news conference at a hotel in suburban Detroit by Lions Coach Monte Clark and the entire Detroit offensive line.

Tackle Keith Dorney said the players and coaches wanted Sims to know they respected his position and supported him, whether he decides to report to practice or not. "We miss you a lot," said Dorney, the Lions' offensive captain. "We're not down on you. We're not trying to sway you."

Sims signed a four-year contract paying him $1.24 million in salary and bonuses, but the fourth-year salary figure has not been negotiated. Sims says Lions General Manager Russ Thomas agreed verbally to negotiate that now. Thomas says he agreed to negotiate only after the end of the current season . . .

Rollie Dotsch, 49, offensive line coach for the Pittsburgh Steelers, will be named coach of the Birmingham Stallions of the new United States Football League Thursday. After the USFL team called a news conference for Thursday, its president, Jerry Sklar, confirmed that Dotsch will be presented as the coach . . .

Running back Chuck Muncie reported to the San Diego Chargers after three weeks of drug treatment and said he anticipates being a starter when the season opens Sept. 12. With Muncie missing, the Chargers moved Ricky Bell into the running-back spot. Bell averaged 2.5 yards on 27 carries in three exhibition games.