The Brewers had already shown interest in a number of middle infielders before Weeks' injury.
"We've been through all of those names, we know who's available and who's not," Melvin said. "We're brainstorming and evaluating the best way to cover ourselves. It's probably not going to be one person. It's going to be a combination of guys."
The Brewers have reportedly shown interest in the Dodgers' Jamey Carroll and Rafael Furcal, though Los Angeles has not been moved by offers so far. The Brewers could also pursue Houston shortstop Clint Barmes, Rockies second baseman Mark Ellis (who has already been traded from Oakland to Colorado this season), Marlins utility man Omar Infante or Mariners second baseman Adam Kennedy.
Kennedy was with Brewers manager Ron Roenicke in Anaheim from 2000-06, and is batting .253 this season with seven home runs, 32 RBIs and a .297 on-base percentage. Among Seattle's wants are catching help or a hitting prospect.
"We don't really know the second-base market," Brewers principal owner Mark Attanasio said Wednesday night. "Doug and his team, really, they look at every iteration possible. I've got to say, we haven't really looked for second basemen because Rickie is an All-Star. It would be like looking for a left fielder or a first baseman."
But Melvin's staff was certainly prepared to jump into that market. The team gathered its pro scouts at Miller Park earlier this month to study the Major League and upper-level Minor League rosters of all 29 teams.
Roenicke and Melvin discussed available players on Wednesday night and again Thursday morning.
"He was making these calls anyway," Roenicke said, "and now that you have a second baseman go down, now these other teams think it's a dire need and they ask for more. It kind of makes it tougher when something like this happens. I don't know if [asking prices] will go up, but I don't think they'll come down."
He added: "All of these things may be answered in a few days."
The immediate in-house option is Triple-A Nashville second baseman Eric Farris, who arrived at Miller Park about an hour before Thursday's game.
The Brewers also discussed Nashville third baseman Taylor Green, who is having a comeback season at the plate. But "he's a third baseman who has played a few games" at second, Roenicke said.
"I'm kind of at a loss for words at the moment," Farris said after arriving. "I'm trying to get it all together. It's been a mad 12 hours for me. I'm trying to get acclimated and have a little fun."
Lopez could temporarily take Farris' spot at Nashville. The switch-hitting Lopez, 31, was with the Rays' Triple-A Durham team, hitting .305 with seven home runs and 37 RBIs. He's had a tough couple of years since his months with Milwaukee, batting .233 for two teams in 2010 and just .216 in very limited duty -- 97 at-bats -- during two stints with the Rays in '11.
Lopez has experience all over the infield and has made 300 big league starts at second base.