(Christian Petersen/GETTY IMAGES)

Harper had one of his biggest games of the fall Wednesday night, going 2 for 3 with a homer and four RBIs. In his last nine games, Harper is 11 for 32 with six walks, two homers, a double, a triple, three steals and 10 RBIs. Harper, going back to junior college, has made it something of a pattern to take a while to acclimate to a new setting before emerging as a dominant force. That seems to be happening again in the Arizona Fall League.

A player’s hot and cold streaks in the fall really aren’t what the Nationals evaluate, though. General Manager Mike Rizzo has been most impressed – in the words of Nationals’ scouts, including his father, Phil Rizzo – by Harper’s advancement on the base paths and on defense. He has been more selective stealing bases and more consistent in the outfield.

“Bryce is playing very, very well,” General Manager Mike Rizzo said. “He’s been a hot streak. He’s playing good defense. His defense has improved dramatically. His base running has improved dramatically. His propensity to steal bases has been terrific. He’s moving great. He feels great. He’s swinging the bat real well.”

While Harper, as he tends to do, has commanded the most attention among Nationals players, the most promising development for the Nationals in the AFL may have come from catcher Derek Norris, who played all of 2011 in Harrisburg. In 11 games, playing in the fall league for the second season, Norris is hitting .361/.457/.583 with two homers.

Norris is widely regarded as the Nationals’ second-best position player prospect behind Harper and a top 100 overall prospect in baseball. His mature, advance plate approach is the main reason – Norris has 344 walks and a .403 on-base percentage in 431 career minor league games. Last year, he said he doesn’t mind striking out looking most of the time because he trusts his batting eye over the strike zone of a minor league umpire.

The main question about Norris in the past concerned his defense. But he has shown, in the Nationals’ eyes, marked improvement behind the plate. During this season, Nationals player development official Bob Boone said Norris had greatly enhanced his footwork and throwing release.

In the AFL, “Norris is catching and throwing extremely well,” Rizzo said. “The pitchers just love throwing to him. We know he can hit. Pitchers love throwing to him. That’s a really exciting package for us going into next season.”

Sammy Solis, the Nationals’ second-round pick in 2010, has allowed 11 earned runs in 15 innings, but Rizzo believes his performance has been better than the results. Solis has been throwing his fastball consistently at 93-94 miles per hour, reaching as fast as 96.

“His stuff has been very, very good,” Rizzo said. “His numbers aren’t great, but his repertoire has been terrific.”

>> Right-handed reliever Rafael Martin has allowed one earned run in six innings, striking out five and walking two.

>> Infielder Zachary Walters is 7 for 43 (.163) with a home run and two walks.

>> Right-handed reliever Pat Lehman, a George Washington alum, has allowed 10 earned runs in 7 2/3 innings, striking out seven and walking two.

>> Left-handed starter Matt Purke, who signed a major league contract after the Nationals took him in the third round this year, has allowed eight earned runs in 2 1/3 innings, striking out one and walking two.