ATLANTA — When choosing between Tyler Pastornicky and Andrelton Simmons in spring training, the Braves said they opted for the more polished offensive player when Pastornicky was named the starting shortstop.
    Now it's time for the better defensive player.
    Simmons is expected to make his debut as the Braves' starter when the team opens a series at Washington tonight.
    Simmons, regarded as one of baseball's top defensive shortstop prospects, was called up after Wednesday night's win over St. Louis. Pastornicky was optioned to Triple-A Gwinnett.
    "They feel like I needed more work defensively," said Pastornicky, who was hitting .248 but already had seven errors.
    "It's never good news, but I've just got to keep grinding. I think I did OK. I don't think I played up to my satisfaction."
    Simmons, 22, almost beat out Pastornicky this spring. He has worked to disprove his reputation as a player with limited offensive potential, even after winning the batting title in the Class A Carolina League last year, hitting .311 for Lynchburg.
    The Braves wanted to see Simmons hit against more advanced pitching. Simmons, a native of Curacao, was hitting .292 at Double-A Mississippi this year, showing he can do more than play strong defense.
    The Braves will be happy if Simmons' offense comes close to the numbers provided by Pastornicky. They're expecting much more on defense, as Pastornicky can't match Simmons' range or exceptionally strong arm.
    "He has special talents," said general manager Frank Wren of Simmons' defensive skills.
    "I just think once the reports started coming in so glowingly, that he was handling that level well, we started at least giving it some thought as to when would be the right time. We continued to call this week and everyone in player development said he's ready. He's ready to help us."
    Wren and manager Fredi Gonzalez said the Braves aren't giving up on Pastornicky, also 22.
    "I think he's improved in some areas," Gonzalez said when asked before Wednesday's game about Pastornicky's defense.
    "He's a work in progress."
    Gonzalez said Pastornicky, who normally hit eighth in the lineup, had performed as well on offense as the team expected.
    Wren and Gonzalez finally decided Pastornicky's defense needs more refinement.
    "There are some areas he could stand to improve," Wren said. "We think he's got a chance to be a real good major league player. But right now, we think he needs more work."
    Simmons has demonstrated he has advanced his offensive skills. He had 26 stolen bases last season but was caught 18 times, an unacceptable ratio. This year, he has 10 steals and has been caught only twice.
    He only has 20 strikeouts with 20 walks and also has improved his on-base percentage (.372).