The 49ers continued Friday to be draft-pick hoarders. Early on the second day of the NFL's selection festival, they traded down again, giving up their higher second-round selection for three other picks.

It's nothing new for the franchise and general manager Trent Baalke. He seems to approach the other NFL teams as if they are payday loan customers, leaving them perpetually in debt to the 49ers with more and more picks.

Yet there is one big advantage to being a draft pick hoarder: You can use one of those extra picks to take a risk. And that's what the 49ers did. They used the 40th overall selection to call the name of Cornellius "Tank" Carradine, a defensive lineman from Florida State.

General Manager Trent Baalke addresses the media during a 49ers press conference at the Palace Hotel in San Francisco, California on Friday, January 7,
General Manager Trent Baalke addresses the media during a 49ers press conference at the Palace Hotel in San Francisco, California on Friday, January 7, 2011. The San Francisco 49ers announced Jim Harbaugh as their new head coach. (Jim Gensheimer/Mercury News)

Carradine is not the hugest of huge risks, to be honest. But he did sustain a serious knee injury in his last game as a college player, a torn anterior cruciate ligament in his right knee. It means that Carradine might not be fully rehabbed and recovered for the start of the 2013 season.

When he finally is healthy, Carradine might turn out to be the second coming of Justin Smith. But if the knee does not snap back, Carradine could be much less. He only started one year of major college football, in his senior season at FSU, after a stint in junior college. So he needs experience and development.

The 49ers are banking on the knee being no problem. And they're willing to be patient with his progress. In Carradine's conference call with Bay Area reporters after being selected, he poo-poohed any notion that it would be a problem, saying the rehab was going just fine. He also revealed the origin of his nickname. And it had nothing to do with his 6-foot-4, 276-pound frame.

"My mom gave the nickname to me," Carradine said. "When I was a kid, I always had a toy army tank I'd carry around and always used it to 'run over' people. So she started calling me 'Tank.' ''

Carradine said his mother still has the toy tank back home in Cincinnati, where he grew up. Now, of course, Carradine should be able to afford bigger toys.

Later Friday, Baalke struck again, wheeling and dealing his way into the 23rd spot of the second round — and taking tight end Vance McDonald of Rice. This is getting to be standard stuff around 4949 Centennial Drive.

In fact, you have to wonder if Baalke might soon appear on one of those reality television shows about compulsive hoarding. It would be pretty dramatic, with Baalke's office crammed from floor to ceiling with draft paperwork and a cleanup crew pleading for an intervention.

Baalke will have none of that. Once a hoarder, always a hoarder. It's working out just fine for the 49ers so far. Read more Mark Purdy at mercurynews.com/purdy