Brogdon played in 75 games his rookie year. Since then, the most he ever played in was 67. He's injury prone. No, it's not one chronic thing like Williams' knee, but the man is injured EVERY year. If that's not prone to injury, I don' know what is.
As for value of now versus offseason...If a team is contending and trades for him now, they get him for 2 playoff runs. If they trade for him in the offseason, they only get him for one. Any team giving up a pick would prefer more than one go at the playoffs with whoever they are acquiring.
In the offseason, it is easier for a team to talk themselves in to the free agent acquisition they an get for cheaper, without giving up a pick, or a draft pick, if circumstances have changed, and they no longer think they can contend, or are just one piece away.
I definitely think his price will never be higher than it is right now.