Bryce Harper, shown here playing for Class A Hagerstown, will compete for a spot on the Nationals opening day roster. (Jonathan Newton/The Washington Post)

There are reasons, sound and ample, why Bryce Harper should not begin the 2012 season in the major leagues with the Washington Nationals. He is 19 years old. He has taken fewer than 600 at-bats as a professional. He has never faced pitching above Class AA. He is, by any normal standard, not ready.

But then there is also the mortar-fire crash of the ball connecting with his bat, and the uncommon maturity he has gained playing against older competition all of his life. There is the immense talent that, when you scrub away his youth and relative inexperience, screams that he can compete at any level. And there is what his manager sees.

When Davey Johnson weighs the factors, he comes to a conclusion that could help shape the Nationals’ offseason and will surely dominate their spring. Johnson left the Florida sun to come here to unusually frigid Texas, but his declaration on the first day of the winter meetings made spring seem vividly near. Johnson believes Harper deserves the opportunity to arrive in Viera, Fla. and compete to make the Nationals on opening day. He believes, essentially, that Harper is not normal.

“I think the main thing is, could he handle it mentally?” Johnson said. “I think, in his mind, he’s already figuring he’ll be starting on the club. He’s done everything in his whole life to compete at a higher level and compete with the best. He’s the kind of individual that probably puts more pressure on himself to perform and expedite the trip to the big leagues. I think he’ll be much more relaxed if he’s there and competing.”

In 1984, when Johnson managed the New York Mets, he worked to convince his general manager, Frank Cashen, that the Mets should promote 19-year-old Dwight Gooden even though he had never pitched above Class A. “Let’s just keep an open mind and see what he does,” Johnson repeated to Cashen.

Johnson got his wish. Gooden made the team, then went 17-9 with a 2.60 ERA in his rookie season, finishing second in the Cy Young vote. The experience — a prodigious, rare talent succeeding despite youth — informs Johnson’s thinking with Harper, who bolstered his case with a dazzling performance in the Arizona Fall League.

“I think this guy’s pretty mature,” Johnson said. “I don’t look at him age-wise like I probably should. But I think he’s going to make this spring very interesting.”

The prospect of Harper making the team, along with other factors, also colors the Nationals’ pursuit of a center fielder. During a four-hour meeting, the Nationals identified three or four potential trade targets, including standout defender Peter Bourjos of the Los Angeles Angels and the Tampa Bay Rays’ B.J. Upton.

The Nationals are prepared to make a trade, but they will proceed with caution and patience. General Manager Mike Rizzo “didn’t panic in July,” when the Nationals nearly traded for a center fielder, one Nationals official said. “And he’s not going to panic now.”

With Harper potentially in the major league fold, the Nationals would feel comfortable shifting Jayson Werth from right field to center field. Even if Harper starts the year at Class AAA Syracuse, the Nationals could use Roger Bernadina in either center or left.

The Nationals do not view Bernadina as a long-term solution. But he is at least a short-term option, one made more palatable by Harper’s imminent arrival and Werth’s capability in center.

“That was one of the reasons that we put Jayson out there” in September, General Manager Mike Rizzo said. “We felt that he played quite well out there. It doesn’t really keyhole us into having to make a trade for a center fielder. We feel that we could have a center fielder in-house already.”

“There’s a chance that we’ve got in-house candidates [to play right field]. Harper and several others could fill that bill, depending on if we deem Harper ready. ”

Another consideration for the Nationals is to try to land a center fielder in their minor league pipeline. In Michael Taylor, Brian Goodwin and Eury Perez, the Nationals have three potential center fielders who are 20 or younger. None is ready for the majors now, and probably will not be ready until 2014. But their presence means the Nationals can afford to consider short-term and long-term options.

“We feel we do have good depth, not only in young controllable players in the majors, but also in the minor league system,” Rizzo said. “But it’s taken us quite a long time to get to the point where we are fairly deep with fairly impact minor league players in the system. We don’t want to erase that with one trade. We’re going to be prudent and careful.”

With Harper, the Nationals may eschew prudence for potential.

“Is he the best candidate out there?” Johnson said. “Is he going to make our club stronger? I’m open to him competing for a spot, whether he can handle it, or whether he makes it until June or July.

“I think you guys asked me last spring, when do you think Harper is going to get there? I said he’s going to have some quality at-bats in the big leagues when he’s 19. He’s 19, isn’t he?”