The 49ers gambled this past offseason when they allowed safety Dashon Goldson to leave in free agency.Goldson, a proven veteran with a knack for making big hits, had been a key component of an outstanding defense in the 2011 and 2012 seasons.Five games into the 2013 season, it's looking like the 49ers' gamble is a winner.Rookie Eric Reid, taken with the 18th overall choice in the first round of the April draft out of LSU, won the starting assignment to replace Goldson in this summer's training camp and now is showing that he, too, can be a big hitter and playmaker at safety the way Goldson was.Reid, however, is just 21 and far less costly to the 49ers' salary structure.In Sunday's 34-3 victory over the Houston Texans at Candlestick Park, Reid made several big hits, had a season-high eight tackles and broke up a pass – that could have been his third interception of the season. With the 49ers intent on stopping the Texans' strong running game, Reid was a key factor Sunday night, coming up numerous times to stop running backs Arian Foster or Ben Tate.His only notable mistake was the pass from Texans quarterback Matt Schaub that he broke to, in front of the intended receiver,...