After officially parting ways with Dashon Goldson last week, the 49ers hosted safeties who ranged from All-Pro (Charles Woodson) to above average (Louis Delmas) to anonymous (Craig Dahl). On Saturday, they signed Dahl, 27, a former undrafted free agent from North Dakota State who quietly started 40 games for the Rams the past four seasons. Dahl signed a three-year contract with undisclosed financial terms. A 16-game starter in 2012, Dahl hopes to fill the same role in San Francisco. The 49ers are seeking a replacement for Goldson, a two-time Pro Bowler who signed a five-year, $41.25 million deal with Tampa Bay on Wednesday. “They told me that there was an opportunity to play in the void at the safety position in the secondary,” Dahl said. “I’m hoping to come in here and mesh well with the secondary and fill that void.”