Kiper mock update: 49ers at No. 13

Mel Kiper has replaced Clemson running back C.J. Spiller with Florida cornerback Joe Haden as the 49ers' choice at No. 13 in his latest first-round mock draft.

I'm updating the pre-combine and post-combine items making sense of first-round choices for NFC West teams, continuing with the 49ers at No. 13:

13. San Francisco 49ers

Mel's latest pick: Joe Haden, CB, Florida

My latest thoughts: Reading too much into Haden's disappointing 40-yard time could be a mistake. Antrel Rolle went eighth overall in 2005 after running a 4.52 among his times (Rolle also had a 4.49). Haden will make another run at the 40 during a March 17 pro day. If Haden does remain available, the value could prove irresistible for the 49ers, who had similar luck last year when Michael Crabtree fell to them. Offensive tackle could be more of an immediate need, but the 49ers have recently shown they'll put more emphasis on value.

Mel's previous pick: C.J. Spiller, RB, Clemson

My pre-combine thoughts: The 49ers do need a return specialist. They could use a change-of-pace running back, too. Spiller would fill those needs and let's face it, mock drafts are mostly about matching teams needs with the prospects available. But as the 49ers found out when Michael Crabtree fell to them unexpectedly, surprises happen. It's important for the 49ers to keep things in perspective here. It's way too early to write off Glen Coffee as Frank Gore's backup. A running back drafted in the first round needs to play, in most cases, and this selection would invite more questions about Gore's role in an offense that ignored him for stretches once Alex Smith became quarterback. It's possible to find return specialists later in the draft. Spiller should be the pick only if the value is there, not just to fill a couple needs.

My post-combine follow-up: Spiller's 40-yard time validated expectations for him. I still wonder whether the 49ers would find enough playing time for him to justify the choice this early. Perhaps that is a good problem to have. However, the top of this draft is more likely to see a run on offensive tackles than a run on running backs. How quickly the offensive tackles come off the board will likely influence the 49ers' thinking in this spot. If the best tackles are gone among the top 12 choices, it's probably a disappointment for the 49ers. General manager Scot McCloughan recently reiterated his belief in the NFL as a big man's game. That doesn't rule out Spiller, but I think the 49ers might prefer to use this pick to get more physical.