Blackmon hit .236 during the spring.
"Charlie's got more time out there than Corey does, and to be honest with you, Charlie may have been our best player the last month of [last] season," Weiss said. "He was the right guy to be out there."
While his offensive numbers lagged in Spring Training, Blackmon arrived at camp slightly faster -- "I don't think I look any faster, but I feel faster," he said -- and he already came with center-field skills. The expansive outfield at Marlins Park was part of the decision to start Blackmon.
"Center field is the essence of outfield play," Blackmon said. "It's something I've always liked doing. You're involved in the game and you see exactly how your pitcher is feeling that day, and it's more fun.
"The more I play there, the surer my reads will be. It's like any part of your game, the more reps you get in game situations the better you'll get. I feel comfortable out there."
During camp, with help from first-base coach Eric Young and special outfield instructors Ellis Burks and Larry Walker, Blackmon improved his reads and efficiency.
"That's one thing he worked extremely hard on, and I think he has a better feeling now of how to get that great jump to the right or left," Young said. "You know at Coors Field or this park, too, if you don't get that good jump, the ball could be over your head and all the way to the wall. We were able to show him on video of Spring Training games that by the end, he was getting better jumps."
Weiss will manage the playing time of six outfielders. Corner guys Carlos Gonzalez and Michael Cuddyer will start most games. Blackmon and Dickerson from the left side, and Drew Stubbs and Brandon Barnes from the right, will divide starts in center and must provide off-the-bench help. Stubbs is more strictly a center fielder than the others.
"If you have to burn a guy late in the game to get the matchup you need, you can do that," Weiss said. "Those guys can run late in the game. They can hit late in the game. They can play defense late in the game.
"I'm going to play it out [with the six outfielders] and see how it works."
There is just one backup infielder, Charlie Culberson, but Weiss noted that backup catcher Jordan Pacheco has played third, first and second; Cuddyer, who is the backup first baseman, has played second and third in the Majors.