INDIANAPOLIS - Though they likely completed most of their off-season activity last week, the Phillies will be characteristically open to further moves during baseball's annual winter meetings, which begin today and end Thursday.

General manager Ruben Amaro Jr., whose approach is to relentlessly explore ways to tinker with the roster, will gather most of his front office in a suite to deliberate decisions large and small. The immediate question is whether to sign a high-end relief pitcher like righthander Brandon Lyon. Amaro pounced once he saw the possibility of deals with third baseman Placido Polanco, catcher Brian Schneider, and utility man Juan Castro, so expect him to be aggressive in filling bullpen needs this week.

"I'm pretty much a bird-in-hand guy," he said Thursday. "I usually like to move quickly."

The GM will also assign various staffers as his liaisons to other front offices to discuss potential trades, he said last week. The Phils will surely monitor the market for Toronto ace Roy Halladay - the week is widely expected to revolve around Toronto's efforts to move the righthander - while deciding whether to reengage in talks to acquire him.

As they try to shape the 2010 bullpen, the Phillies will negotiate with the agents for Scott Eyre and Chan Ho Park and explore potential "low-risk, high-reward" signings, as they claim to have limited payroll flexibility.

Pedro Martinez, who last week expressed an interest in returning, could also be a candidate to augment the pitching staff, provided his contract demands are modest.

Contact staff writer Andy Martino at 215-854-4874 or amartino@phillynews.com.