One option staring the Phillies in the face is to move Brett Myers back to the closer's role (where he has said he would rather be) and look to re-sign Kyle Lohse to take Myers spot in the rotation. It weakens the rotation, but at least the Phillies would have a more reliable closer in place, although Myers had some injury issues last season as well.
Perhaps the best option would be to look elsewhere.
The first option that generally comes up when teams talk about acquiring a reliever is Washington closer Chad Cordero. While he hits some rough stretches, Cordero is one of the better young closers in the game and could be had for the right price. The right price would be a little steep and could include someone like Carlos Carrasco. There's another bullpen that is deep and could be prime for dealing a pretty decent reliever who has either been a closer before or has the potential to be a closer in the future and that's the Milwaukee Brewers. Eric Gagne, Derrick Turnbow, David Riske, Solomon Torres, Guillermo Mota and Brian Shouse are the top bullpen candidates and the Brewers are likely to look at dealing one of them as the season approaches.
The Rockies Brian Fuentes is one option, but he's slightly fragile as well. The downside is that he wound up on the DL last season and lost his closer's role to Manny Corpas, but keep in mind that he's been a National League All-Star in each of the last three seasons. Even with his down season last year, he saved 20 games for Colorado.
Possibly the highest priced of potentially available closers is Huston Street from the Oakland A's. There were rumors all winter long that Oakland might deal Street, but the demands were always pretty high and the Phillies don't want to shop in that type of market right now. If Lidge is going to be out long-term, the Phillies may start to think a little differently about who they would offer in a deal, making Street more of an option.
Since the high part of the scale isn't where the Phillies want to shop right now, what about the other end? One name out there that's interesting is Mike MacDougal of the Chicago White Sox. MacDougal hasn't been in a closer's role since 2005 and has put up some pretty weak numbers in his effort to return from injuries. He might be worth a shot, but wouldn't really help the Phillies to feel overly secure about the back end of the bullpen.
The internal options aren't too bright. Ryan Madson has had a couple of shots at closing and hasn't done well in those opportunities. J.C. Romero would possibly be another option, but he's got somewhat of a checkered past and is simply more suited to being a left-handed specialist rather than stepping into the closer's role.
If Lidge truly will miss only three weeks, the Phillies can likely piece things together. If he's out longer, they can likely limp their way through it - no pun intended - but it can't go on for too long or else the Phillies will be in trouble. Even if he is going to be back in three weeks though, the Phillies will have to keep a close watch on their closer's role and should probably keep asking around to see who is shopping closers and at what price. If closer's aren't available, but starters are, the Phillies could use the Myers option again, but they swear they want to keep him in the rotation.