SANTA CLARA, Calif. -- Tight end Vance McDonald, a second-round draft pick by the 49ers, has been playing extremely well in the past few weeks.His statistical impact hasn't been great. The TCU product has five catches for 66 yards. However, San Francisco offensive coordinator Greg Roman said McDonald is making a strong impression because he is making strong strides as a rookie."We've asked a lot of him the past couple weeks, really the past three weeks," Roman said.