The Facts: Thin at receiver, the 49ers are looking at reinforcements. The team will work out Robinson later this week, a league source said.

Diehards Line: The 49ers had showed interest in Robinson during the 2012 free agency period, but he signed a five-year deal with the Jaguars instead. The Jaguars released him in March after Robinson suffered multiple concussions in 2012. Robinson has worked out for the Dolphins, Jets, Patriots and Lions in recent weeks. The 49ers also have worked out another receiver with a concussion history, Austin Collie. Collie remains a free agent. ... As Bee staffer Matt Barrows explained, the interest is fairly obvious; the team went through its second straight practice Wednesday without receivers A.J. Jenkins (already struggling before he was hurt), Kassim Osgood and Kyle Williams, all of whom suffered muscle strains in the last week. Another receiver, rookie Quinton Patton, has been practicing with a broken finger on his left hand. Two of their top receivers, Michael Crabtree and Mario Manningham, are returning from major injuries and both currently are on the physically unable to perform list.