Navy quarterback Bill Byrne incurred a broken right fibula in Saturday's 18-17 loss to Notre Dame and will miss at least two weeks, it was found yesterday. It is uncertain whether he will return for the Army game Dec. 1 in Philadelphia.

Byrne was injured trying to tackle Notre Dame linebacker Rick DiBernardo late in the third quarter after DiBernardo had intercepted Byrne. In the resulting pileup, Byrne's foot was bent backward.

Preliminary X-rays taken at the game in East Rutherford, N.J., did not uncover the extent of his injury. Yesterday, X-rays performed at Annapolis revealed the fracture.

Byrne, the ECAC rookie of the week four times, has started every game for the Midshipmen this season. Already he has set Naval Academy records for touchdown passes in a season (11) and single-game yardage (340 against Pittsburgh). With 1,425 yards, he is 112 yards shy of John Cartwright's single-season passing yardage record.

He will miss this week's game at Syracuse and the following Saturday's home date with South Carolina. The Midshipmen then have an open date before the Army game.

This is the second vital injury for Navy this year. In the second week, premier running back Napoleon McCallum was lost for the season with a broken ankle.

"Any time you lose someone so prominent, it's going to take you a step backwards," Coach Gary Tranquill said. "Napoleon went out early and we had a chance to regroup. But with Billy going out so late in the season, you don't like to make any changes."

Bob Misch, a sophomore from Cleveland who alternated with Byrne early, will make his first college start in Byrne's place. Misch has thrown 58 passes this year, completing 23 for 218 yards, one touchdown and one interception.

"I've prepared myself to play every week in case Billy wasn't getting the job done or if he got hurt," said Misch. "It's the worst way to have to play, but I'll be ready."

"He (Misch) has played quite a bit this season, and I feel comfortable with him in there," Tranquill said. "Obviously you don't like to lose your starting quarterback, but Bobby is very capable."

Mark Colby, who has done all of Navy's punting for three years but went down injured in the last minute of the Notre Dame game, is "very doubtful" for Syracuse . . . Tranquill again maintained the Irish should have been penalized for running into Colby, and for taking too much time on the winning field goal that ensued. Furthermore, the coach said, he noticed in game film that Notre Dame had 12 men on the field when it scored its second touchdown.