The 49ers weren't exactly certain what they had in Vance McDonald going into the 2013 season.The rookie tight end from Rice was certainly big enough to play his position (6-foot-4, 267 pounds) and strong enough (he had the best bench-press performance of any tight end in his draft class). But would he have the all-around skills and blocking abilities that the Niners prized so much in departed free agent Delanie Walker, who had been the team's versatile "Swiss Army knife"?The early answer: No. McDonald, who was used by Rice as a tight end, wide receiver, slot receiver and even running back on occasion, had to learn to become a professional blocker and his hands were inconsistent. But by the end of the season, McDonald had come a long way. Now, as the team begins preparations for next season, McDonald should be a much more valuable and versatile player for the 49ers offense.By the end of the season, McDonald was getting praise for his blocking and even stepped into an emergency role as a blocking fullback in the playoff victory over Carolina when Will Tukuafu was knocked out of the game with an injury. After that game, San Francisco head coach Jim Harbaugh said McDonald "blocked...