VIERA, Fla. -- Bryce Harper took his physical Monday morning and then participated in his first Spring Training workout, which was a sight to see. About 100 fans and a handful of media watched Harper's every move intently.

Harper, the first overall pick in the 2010 First-Year Player Draft, arrived at the Nationals' complex around 11 a.m. ET. He started stretching with the rest of his teammates on Field 4 for several minutes before going off to Field 2 to take batting practice.

With assistant general manager Bob Boone, farm director Doug Harris and advisers Pat Corrales and Davey Johnson observing, it's easy to understand why Harper is called the LeBron James of baseball. At just 18 years old, the outfielder put on a show with the bat. Harper hit almost nothing but line drives and a few of his balls went over the fence.

Johnson came away impressed by what he saw, and he has watched Harper play baseball since the latter was 15. Johnson actually saw Harper win a home run contest in Florida using a wood bat at that same age, facing teenagers who were at least two years older than him.

Johnson went so far as to predict that Harper will be in the big leagues by this time next year. General manager Mike Rizzo already announced that Harper most likely will not make an appearance in Washington this season.

"He is a special talent. There is no doubt about it," Johnson said. "He has tremendous bat speed, his hand-eye coordination is outstanding and he is short to the ball. I really like his approach. He is very mature.

"He does a lot of things right. All he needs to do is get used to the professional life, where you are on the road a lot, playing every day and getting into the groove of things."

After putting on the hitting display, Harper took a sip of water and walked to Field 1. Batting practice was already taking place when Harper took a break to talk to first baseman Chris Marrero. As it turns out, they know the same circle of people in baseball.

"He seems like a nice guy," Marrero said. "He seems very humble. He is going to go out there, work hard and do the same thing as me -- impress everyone here."

After a brief conversation, Harper and several of his outfield teammates went behind a fence and received a few tips from third-base coach Bo Porter. After a 10 minute session, Harper tried to leave the complex.

One problem: there were a bunch of fans trying to get his autograph.

It was a mob scene. It got to the point where manager Jim Riggleman had to politely tell the fans, "Bryce has one more minute because he has to go into meetings." It took a number of security to put a halt to the impromptu autograph session.

Rizzo was watching the scene in disbelief.

"[Harper] will never come out of [the left side of the field] again," Rizzo said.

The autograph session lasted for about five minutes before Harper walked back to Space Coast Stadium with John Dever, the club's senior director of baseball media relations.

Both Dever and Harper needed security to get back to the stadium. Jim Gibson, one of the security guards escorting Harper, said he started to feel a little tired physically while walking back to the stadium, which is about 150 yards from the complex.

"There were so many fans that were pushing and shoving, but he is going to be there all week and they just keep trying to get him." Gibson said.

Said Riggleman, "It's a great thing, but it's too much for him. He couldn't have gotten out of there. He needs to be able to sign a few autographs and get back to the stadium, do the things he needs to do in the weight room, have something to eat, things like that. [If we didn't put a stop to the autograph session], Bryce would have been out there for an hour. It just can't be like that. He is going to have to sign a few like he did and let him get out of there."

The Nationals already have a game plan for Harper during the exhibition season. He isn't likely to start many Spring Training games in the Major Leagues and will see most of his action on the Minor League fields, playing both left and right field.

"We may give our regular outfielders a day off and have a start for him [in the Major Leagues]," Riggleman said. "In the next week to 10 days, he will get some at-bats."