Can Harper be an impact player for Washington? Entering Friday's action, the left-handed hitter is batting .408 with 23 home runs and 68 RBIs for the College of Southern Nevada.
Rizzo acknowledged that Harper, 17, is being seriously considered for the first overall pick in the Draft, which will be held from June 7-9.
"We still have a month before the Draft. A lot of things can happen -- injuries, poor performance. Something else could happen," Rizzo said "We are just not prepared to commit to any player yet. We are scouting them up to June 7 and probably will not make a decision until soon before that. I wouldn't say we are leaning toward anybody. We are leaning toward a handful of people.
Early this month, Rizzo acknowledged that he scouted Harper in Las Vegas, Nev., and came away impressed.
"He played great," Rizzo said. "He has great energy, great tools and he is one of the five or six guys we are talking about taking with the first pick. He has great bat speed and great leverage power. He is already comfortable with the wooden bat."
Rizzo saw Harper perform behind the plate and in right field. Rizzo said Harper is above average at both positions.
"He plays both of them extremely well," Rizzo said. "He has great talent behind the plate and great talent in the outfield."
Rizzo dismissed reports about character concerns regarding Harper.
"He is moving 110 miles per hour all the time," Rizzo said. "He really plays hard between the lines. He is a young player with a big upside. We have no problem with Bryce Harper's character.
"We know him as well as anybody. [Assistant general manager] Roy Clark and [scouting director] Kris Kline have been doing this Draft stuff for many years, and if they are not concerned with it, I'm not concerned with it.
"I met the kid personally. I met the mom and dad personally. I adore how they interact as a family. The dad is an iron worker. Bryce is a hard-working, blue-collar guy and the kid brings his lunch pail every day."
Rizzo declined to specify other players the Nationals might be considering for the top pick. But according to a baseball source, the club is taking serious looks at pitchers Drew Pomeranz of the University of Mississippi and Jameson Taillon of The Woodlands (Texas) High School and shortstop Manny Machado of Brito High School in Miami.
In 12 starts for Ole Miss, Pomeranz, a left-hander, is 6-1 with a 2.17 ERA. He also has struck out 112 batters in 74 2/3 innings.
Tallion, a right-hander, is known for his fastball, slider and changeup. His fastball is clocked in the mid-90s.
Machado is considered a five-tool player who could also play third base. According to the Miami Hearld, Machado earned first-team Class 1A All-State honors last season after hitting .636 with eight home runs and 53 RBIs.
"In each round, we are looking for a player who has the best chance to be an impact player in the Major Leagues," Rizzo said. "That's when we talk about upside, tools and those types of things.
"Makeup is huge. Makeup allows your talent to come forth and make it all the way to the Major Leagues. Talent without character doesn't work. Your lack of character will make you stumble somewhere along the line."