NL Notes: Guerrero, D’backs, Rockies, Peralta, Nats, Marlins

For the latest on negotiations between MLB and Japan's Nippon Professional Baseball on the posting fee arrangement — which has major implications, in particular, for highly-regarded starter Masahiro Tanaka — check out this update from Ben Badler of Baseball America. We'll round out the evening with a variety of links from around the National League:

• Alexander Guerrero is dealing with a hamstring injury in his Dominican Winter League stint, tweets Ken Gurnick of MLB.com, and GM Ned Colletti indicated that the missed time could postpone the Dodgers' decision as to whether he'll play short or second next year. That decision — or, potentially, the inability to make it — could seemingly have an impact on Los Angeles' off-season shopping list.
• The Diamondbacks are down on the free agent market, reports MLB.com's Steve Gilbert. "I've spoken a little to our own free agents," said GM Kevin Towers. "But from the looks of where this free agent market is right now and where it's headed, it's not a place where I want to do a lot of business." Gilbert notes that the club has made an offer to infielder Eric Chavez, but that he is still mulling interest from other landing spots.
  
• The Rockies are implementing a new player development structure, reports Thomas Harding of MLB.com. In lieu of roving instructors, the standard in baseball, Colorado will employ "developmental directors" who will each be responsible for a given team and look to prioritize skill development rather than minor league game outcomes.
• Discussing the club's recent signing of Jhonny Peralta, Cardinals GM John Mozeliak explained that a thin shortstop market left Peralta as the best fit for the club. While he said the club considered his PED suspension, he opined that "I don't think it's the Cardinals' responsibility necessarily to be the morality police on potentially future employment." As Peralta admitted his violation of the league's policy and paid his penance, said Mozeliak, "at this point in the game, there's nothing that says he can't go play or isn't free to go sign with another club."
• Mozeliak also said that the club looked around at possible trades, but found the cost prohibitive, tweets Stan McNeal of FOX Sports Midwest. 
• In a well-argued set of responses to fan questions, Adam Kilgore and James Wagner of the Washington Post took stock of a wide range of issues facing the Nationals. Among the thoughts offered relate to the second base position. The Nats are well-situated to add Robinson Cano, says Kilgore, and the move makes some sense. But Kilgore explains that such a scenario remains largely unlikely. Meanwhile, fallen keystoner Danny Espinosa has relatively minimal trade value, Wagner offers. His value to the organization, in terms of upside and as a competitor/backup option to Anthony Rendon, probably outweighs what he'd return.
• The Marlins are mulling over a minor league offer to infielder Scott Sizemore, reports Juan C. Rodriguez of the Sun Sentinel. Certainly, Miami would figure to have the inside track on players looking for a legitimate chance to see big league time at second or third.
• Miami has not only lured "superscout" Jeff McAvoy away from the Rays, but sources tell Jeff Passan of Yahoo! Sports that the club will add Mike Berger from the Diamondbacks in a vice president role (Twitter links). This makes for a quiet but outstanding off-season, opines Passan, who notes that the organization could look quite different if owner Jeffrey Loria gives new GM Dan Jennings more authority than was afforded predecessor Larry Beinfest.