In ranking the 49ers' greatest needs in the draft this week, ESPN.com's Bill Williamson of course put cornerback and wide receiver at the top of the list.Then came (in order) pass rusher, interior offensive line, inside linebacker, quarterback, safety and defensive line. There's a logical reason for every need, and with six of the first 100 choices – and 11 overall – the 49ers will have ample opportunity to address multiple positions over the three days of the draft.The interior offensive line is an obvious area of concern because of the departure of veteran center Jonathan Goodwin and the fact left guard Mike Iupati is entering the final year of his contract. Many NFL analysts have the 49ers going after USC center Marcus Martin in this draft.But Daniel Kilgore would say that's not necessary.Kilgore, a 6-foot-3, 308-pound fifth-round pick of the 49ers in 2011 out of Appalachian State, is the heir apparent to Goodwin and is eager this offseason to prove the center job is his.Kilgore, who signed a three-year contract extension this offseason, has backed up Goodwin and been used at guard and across the line as an extra blocker. Now he's ready to take a lead role in the...