Anthony Randolph fits the criteria to fill a weakness that the Spurs currently have at the 4 position. (I see Duncan as a 5 now.) The Spurs have a hard time matching up with Serge Ibaka, Pau Gasol, Chris Bosh, Josh Smith, Kevin Garnett's of the NBA. Clearly, Bonner, Blair, Diaw have a hard time with those players.
Randolph is a 23 yr old ,with 4 years in the NBA, and 6'11" with a 7'3" wingspan. He can run the floor, make FT's, dribble the ball and block shots.
Anthony Randolph is a restricted free agent with the Timberwolves. He earned $2.9 million this year. The qualifying offer from the Timberwolves would be $4 million. Will the Timberwolves keep him? The Timberwolves had Kevin Love, Derrick Williams, Michael Beasley, and Anthony Tolliver looking to play the 4 position. Tolliver is a free agent and Beasley is a restricted free agent. I'm guessing that he'll be a free agent.
But, Randolph has been on 3 teams and never played well, you say. I decided to look at Randolph's stats and compare them to Kevin Garnett's stats thru the 1st 4 years for each. The link is http://www.basketball-reference.com/play-index/pcm_finder.cgi?request=1&sum=1&p1=garneke01&y1=1999&p2=randoan01&y2=2012#per_minute::none. The stats show that per 36 minutes that Randolph shoots a little worse, gets to the FT line more frequently, is a better rebounder, a poorer passer, and more foul prone at the same stage in their careers after 4 years in the NBA.
I don't see any better options for the Spurs that won't cost more than the $4-5 million Randolph will garner. Carl Landry, J.J. Hickson, Jason Thompson, Darrell Arthur, I believe will all be more expensive. Hopefully, the Spurs will shed Bonner to make room for a player like Randolph come July 1st.