A small, quiet crowd was soaking up the sunshine on the back fields at the Rockies' spring training complex. Suddenly, there was a startling crack of the bat, followed by gasps. And then the chatter started. "Did you see that? Holy cow! Who is that?" an elderly man in a floppy hat asked of no one in particular. The answer came from a middle-aged man wearing a Rockies cap. "That's their young catcher," he said. "Kid's got some pop in his bat." The kid is 24-year-old Wilin Rosario. Playing that day against the Diamondbacks' Triple-A team, Rosario rocketed the ball over the five-story batter's eye beyond center field. Fans soon began estimating the distance of the home run. One man guessed 430 feet, another 450, another 470. "At least 430 feet," said Rockies pitching coach Jim Wright, who witnessed the blast. "Pretty amazing power, huh?" Although it's still unclear whether Rosario can develop into a serviceable defensive catcher — he had 21 passed balls and 13 errors a season ago — there is little doubt about his prowess as a slugger. "He's got, like, stupid power," said Rockies all-star left fielder Carlos Gonzalez. Rosario hit 28 homers last season, fourth most in major-league history by a rookie catcher. That's more than Carlton Fisk (22), Buster Posey (18) or Gary Carter (17) hit as rookies.