Don’t look now, but the Milwaukee Brewers have turned the NL wild-card race into something worth watching. It wasn’t that long ago that the Brewers had a commanding six-game lead over their closest pursuers and were playing well enough to make the idea that they would blow that lead seem silly. The focus wasn’t on September so much as October, and what a team with power and two excellent starting pitchers could do in a short series. Their statistical shot at making the postseason, which hovered above 80 percent for two weeks and peaked at 94.5 percent on September 1-the day after CC Sabathia twirled his most recent shutout-is now down to 73.2 percent following a three-game losing streak, including back-to-back heartbreaking defeats at the hands of the Cincinnati Reds. The wild-card race now legitimately features four teams:

Brewers     82  63  .566   ---
Phillies    79  66  .545    3
Cardinals   78  66  .542   3.5
Astros      78  67  .538    4

(By the way, I messed up a similar chart in yesterday’s column, greatly inflating the Blue Jays and Yankees chances in the AL races. My apologies, and my thanks to the readers who caught the error and the editors who fixed the chart.)

The last two games have illustrated the Brewers’ primary weakness, their bullpen. While they have received good work from Salomon Torres and Brian Shouse for most of the season, mentioning that merely highlights the fact that their two best relievers are Salomon Torres and Brian Shouse. Torres blew Monday’s game, and while he bounced back to pitch well last night, the lack of depth behind those two was exploited in extra innings.

The fact is, Ned Yost isn’t riding CC Sabathia for kicks; he’s doing so because his bullpen is not only the weakest part of his team, but probably the weakest pen of any above-.500 team in baseball. He has two moderately effective journeymen relievers, and then an assortment of less effective journeymen relievers. The Astros at least have Jose Valverde missing bats in the ninth inning, the Cardinals have the homegrown Chris Perez, and the Mets have some effective matchup pitchers in front of Luis Ayala. The Brewers have guys who walk far too many batters and don’t strike out nearly enough of them. Any game in which Ned Yost has to go to the mound carries with it the potential for disaster. Yost takes criticism for his handling of the pen, and not undeservedly, but you can’t run from the fact that the pen, assembled from spare parts by Doug Melvin-a decision I did not criticize-isn’t championship-caliber, or anything close.

The Brewers’ struggles open the door for the Phillies, the Cardinals, and even the Astros. The Phillies are particularly well-positioned to effectively create a second path to the postseason for themselves; they host the Brewers for four games starting Thursday, and they miss Sabathia in that series. Without wishing to foster panic, I wonder if Yost wouldn’t have been well-served to plug in Seth McClung or Carlos Villanueva or Zach Jackson for today’s matinee against the Reds, pushing Sabathia into the Phillies series to face Chase Utley, Ryan Howard, and company. The Phillies will head into that matchup needing only to take three of four games to make the wild card a realistic option for them, and with Sabathia not in the picture, their doing so is more likely.

The Cardinals were left for dead just last week, but thanks to Albert Pujols‘ ridiculous hot streak-he’s hitting .455/.533/.935 since August 15, and has delivered a 1284 OPS in September-they’ve managed to stay in the race. Pujols has hit homers in three straight games as the Cards cut the Brewers’ lead to 3½ games since Saturday, a fact that has largely gone unnoticed in the race to make Carlos Delgado-a player not half as valuable as Pujols-an MVP candidate. Adam Wainwright‘s return has given them a rotation anchor, and they’ve won all four of his starts since he came back August 22. It is another top-heavy roster in St. Louis, and they have some of the same bullpen issues that the Brewers do, but they also have the best player in baseball and are just three back in the loss column. A soft schedule-five games with the Cubs and 13 against sub-.500 teams-can’t hurt them.

The Astros have lost just once since I eviscerated their 2008 plan last week. Regardless, they have still been outscored on the season, are in tough shape because they’re chasing multiple teams, and they still don’t have anything resembling a playoff roster. They do have a healthy Roy Oswalt-good for a 2.20 ERA in nine starts since coming off the DL, including an active 23 1/3 scoreless innings streak. Valverde allowed six runs to the Pirates in the ninth inning on July 21; since then, he’s made 20 appearances and been unscored upon in 19 of them, converting 16 straight save opportunities. Wandy Rodriguez, Brian Moehler, and Randy Wolf keep grinding out average starts, and while I wouldn’t bet on the latter two in the medium or long term, they have pitched effectively this year, and this year is what matters in Houston. They’re 31-11 since July 23, which is comparable to what the 2004 team did in pushing its way to the wild card and eventually the World Series. They’re the underdog in this mix, but it is finally time to take them seriously.

The Brewers are the best team in this group, although when you look more closely, it becomes clear that the push to anoint them as being on par with the Cubs was misguided. They’re still too right-handed, they still don’t play defense, and their bullpen is bad. They have two great starters and they hit home runs, and with a three-game lead and 17 to play, they control their own destiny. This weekend’s series is critical; merely a split would be a successful trip.

Keep something else in mind: that series is the last time any two of these four teams will play each other this season, something of a common theme as we head into the last few weeks of the NL season. The four wild-card teams above have just one series left among each other. The Mets don’t play any of these teams, either. The Cubs and Brewers have just three games left against each other. The Dodgers and Diamondbacks are done with head-to-head play as well. The Cubs and Cardinals do hook up this week and next weekend, but for the most part, the National League playoff contenders will spend their days playing the Pirates, Reds, Padres, and Giants. It’s a win for scoreboard watchers, but an unfortunate loss for fans of big September series.