NL Notes: Garza, Pirates, Prado, Padres

Here's the latest news and notes from the National League:

• Matt Garza, number seven on MLBTR's 2014 Free Agent Rankings, is slated for one or two additional minor league rehab starts after an abbreviated outing yesterday, reports MLB.com's Carrie Muskat. Garza threw 66 pitches (40 for strikes) over 3 1/3 innings for Double-A Tennessee allowing three hits and two walks. "He felt great and everything, but not real efficient," Cubs mangager Dale Sveum said. "Right now, we have to get him built up to get to the fourth, fifth and hopefully sixth inning." Gordon Wittenmyer of the Chicago Sun-Times tweets Garza is expected to throw 85-95 pitches in his next rehab start, which will come next week for Triple-A Iowa.
• Pirates second baseman Neil Walker is set to return from the disabled list tomorrow and Rob Biertempfel of the Pittsburgh Tribune-Review doesn't expect utilityman John McDonald to be designated for assignment to create space on the 25-man roster. McDonald, hitting only .067/.176/.100 in 34 plate appearances this year, would have to clear waivers while infielder Jordy Mercer still has minor league options available. "I think the term general managers use is you want to maintain all of your assets," manager Clint Hurdle said. "You don't want to release somebody if another guy has options. We're mindful of that."
• Despite a slow start offensively, the Diamondbacks are already seeing dividends from their four-year, $40MM investment in Martin Prado, writes the Atlanta Journal-Constitution's Steve Hummer. 
• The Padres, who have the 13th overall pick in next month's amateur draft, aren't concerned that the perceived top players will be off the board when it comes their turn, according to Corey Brock of MLB.com. "There's probably more balance [in the Draft] than people give it credit for," said Chad MacDonald, vice president and general manager of player personnel, who will preside over the Padres' draft. "There are a lot of high school hitters out there. I think people are quick to grade a Draft." In addition to their area scouts and cross-checkers, the Padres have had GM Josh Byrnes, vice president/assistant GM AJ Hinch, and senior vice president Omar Minaya in the field scouting players.