Because the NFL is a what-can-you-do-for-us-now league, Kendall Hunter is going to have to earn back his old job with the 49ers.After tearing his Achilles' tendon in a game last November, Hunter missed the rest of the season – including the Super Bowl – and watched rookie LaMichael James take over his backup job behind starting running back Frank Gore.Now that Hunter is back on the practice field again with the 49ers, he'll have to prove he still has what made him the Niners' No. 2 back: the speed, quickness and toughness that allowed him to run both inside and outside in the San Francisco offense, even though he's just 5-foot-7.Hunter was activated Saturday from the physically-unable-to-perform list and resumed practicing with his teammates. When he joined the huddle for the first time Saturday, the members of the starting offensive unit gave him a round of applause, reported Eric Branch of the San Francisco Chronicle.Though James played well in Hunter's absence, 49ers head coach Jim Harbaugh said Hunter is penciled in as No. 2 on the running back depth chart behind Gore for the time being."He is the No. 2 guy in terms of assignments," Harbaugh told Bay Area media....