THE SIDELINES : It’s Official--Bishop to Retire

Veteran Denver Broncos offensive lineman Keith Bishop has formally announced his retirement, according to Bishop’s agent.

Bob Warren, based in Denver, said Thursday that the two-time Pro Bowler plans to launch a career in coaching and has sent letters to the Broncos and the NFL informing them he is ending his playing career.

Bishop, 33, plans to serve this fall as a graduate assistant coach at Baylor University, his alma mater. He has been attending classes there since February.

The announcement marked the final development in a strange series of events since last season.

After signing a five-year, $3.18-million contract in September, 1988, Bishop began last season as the Broncos’ starting left guard. Six games into the season, he suffered back spasms and was replaced in the lineup by rookie Doug Widell. Teammates confided that Bishop was bitter about his demotion, but Bishop steadfastly refused to discuss the situation publicly.