Dilfer said he's been considering some post-football different options, but declined to elaborate.
"I think in the next few days there will be a formal announcement on all those things," the former Fresno State quarterback said.
"I think everybody I've talked to says (camaraderie is) the hardest thing to get away from, just the locker room, just being around the guys each day, the routine of the season. But I knew this time was coming, and here it is."
Dilfer, 36, played the 2000 season with the Ravens, who beat the New York Giants in Super Bowl XXXV. He was a free agent following the 2007 season, but did not sign with any team.
Dilfer started six of his seven games for the 49ers last season, throwing for 1,166 yards, seven touchdowns and 12 interceptions. He completed 55.5 percent of his passes for 20,518 yards in his career, throwing 113 touchdown passes and 129 interceptions.