Do the Orioles or Nationals have a better chance of returning to playoffs?

As the season’s final month arrives, the looming question remains: Who has a better chance of returning to the postseason, the Orioles or the Nationals?

The Orioles are chasing two pitching-rich teams - the Red Sox and Rays - in their own division and another, Cleveland, that can’t hit. The Nationals are at point where they need a winning streak and a collapse from one of the three contenders in the National League Central.

We will know more soon about who the Nationals will be chasing. After tonight, the Cardinals’ next three series are against the Pirates twice and the Reds once.

The races in a nutshell:

* The Pirates haven’t had a winning in season in two decades, and their biggest challenge is to avoid the end-of-season collapse that they’ve had in each of the last two seasons. ... They added Marlon Byrd and John Buck, but don’t they need to fortify their rotation? Lefty Jeff Locke looks tired and hasn’t won since July 21. Gerrit Cole is getting extra rest between starts and Wandy Rodriguez doesn’t appear to be coming back from injury. That leaves A.J. Burnett, Francisco Liriano and Charlie Morton as their most dependable starters, and Morton says he’s not totally comfortable throwing curveballs 15 months after elbow surgery. ... Their leadoff batter, Starling Marte, is still two weeks away from returning from a hand injury.

* The thought here for the last couple of weeks is that the Cardinals pitching staff is wobbly, but they keep getting it done, despite inexperience in the rotation and bullpen. There’s a reason the Cards have been trying to trade for the Nats’ Dan Haren. ... Jake Westbrook is hurt. Joe Kelly is doing well, but needs to go deeper into games. Shelby Miller has struggled, although he looked good in his last start. Lance Lynn’s ERA has been near 5.00 in each of the last three months. Manager Mike Matheny is juggling the inexperience of Carlos Martinez, Michael Wacha and Tyler Lyons at the back of the rotation. ... In the bullpen, Trevor Rosenthal’s innings are piling up while Seth Maness has become a high-wire act. Still, the Cardinals’ rotation allowed them to win three of four from Atlanta, as well as the first two games of their series with Cincinnati.

* The Reds have to be feeling the most pressure of all the teams. They won the division in 2010 and 2012, but didn’t win a playoff series. ... Ryan Ludwick is back to help the offense, but he’s still in spring training mode. ... Starter Johnny Cueto is rehabilitating an injury, but there might not be enough time in the minor league season to stretch him out as a starter. So the Reds might make him a relief pitcher. And that makes sense, given that Jonathan Broxton is out for the season.

* The Diamondbacks lost valuable ground by losing five of seven during a trip to Cincinnati and Philadelphia, but they’ll get a chance to rebound with a soft schedule: From here, they play the Giants for seven games, the Rockies six and the Padres five.

* The Rays expect pitcher Matt Moore to return to the rotation Sept. 3, and that means their biggest rotation question will be Jeremy Hellickson, who has been inconsistent all season. David Price, Chris Archer and Alex Cobb are fine. ...The Rays need to survive a 10-game trip to the West Coast in early September when they play Oakland, Seattle and the Los Angeles Angels.

* Cleveland’s problem is scoring run. In August, the Indians rank 14th in run production in the American League. They rank last in team batting average. Michael Bourn isn’t getting on base enough. Nick Swisher isn’t hitting in the cleanup spot. Ryan Raburn, Carlos Santana, Jason Kipnis and Lonnie Chisenhall have cooled.

* Oakland lost its best hitter, Josh Reddick, to a wrist injury and replaced him with Daric Barton, a first baseman who hasn’t had regular playing time with the A’s for three seasons. Barton got two hits in his return to the big leagues. ... Somehow, the A’s keep winning. Their pitching gets a boost when starter Brett Anderson comes back to the bullpen. Bartolo Colon joins the rotation Thursday. ... After a schedule that includes a stretch vs. Detroit, Texas and Tampa Bay, the A’s have a good September: They get to play the Twins six times, and the Angels and Mariners three each.

* The Yankees are mathematically in the wild card race, but how can they win when their ace, CC Sabathia, is getting rocked and Phil Hughes has a 5.00-plus ERA since mid-May?