This can be a good move for the 49ers.
The 49ers seemed more likely to take their chances on a return specialist in the draft. That was just my feel. Ginn's contract was one potential issue. But this deal makes sense from a personnel standpoint because Ginn has first-round talent. He simply didn't fit into the Dolphins' plans after Bill Parcells took over, and he was expendable once the team added Brandon Marshall.
Ginn gives the 49ers a talented complementary receiver -- perhaps in the No. 3 role -- and a potentially explosive returner. His acquisition also shows that the 49ers can make moves without a general manager. Scot McCloughan departed last month, leaving personnel director Trent Baalke in control. Adding Ginn stands as a proactive move. It's a sign the 49ers are operating as usual.
The 49ers haven't had a mercurial receiver with the ability to stretch the field. Ginn has his limitations, obviously, or the Dolphins would have kept him. He needs to become more consistent catching the ball. But he does instantly provide a speed element to the receiver position. The 49ers aren't counting on him to even be the second receiver, but Ginn adds another young player to the offense, and one fitting a profile that differs from what the team already has.
This is a make-or-break year for quarterback Alex Smith. Arming Smith with a diversified collection of weapons can only help him. Imagine if the 49ers added Clemson running back C.J. Spiller in the draft.
Note: Jay Glazer of Fox Sports tweeted news of the trade, reporting that the 49ers will send a "late-round pick" to Miami. I have confirmed the trade through a league source.