By DANIEL DULLUM

Beware the spoiler.

This weekend, the Oakland Athletics host Houston in their quest to regain first place in the American League West. On the surface, this would appear to be favorable to the A’s, since the Astros are fourth in the AL West with a 61-79 mark.

Baseball history tells us, though, that sub-.500 teams can be difficult in September. No pressure to speak of, call-ups looking to make a name for themselves, etc., and the Astros are on a four-game winning streak.

And, the Astros have former A’s prospect Chris Carter at first base and DH, with 33 homers this season to date. So, beware the boomerang as well.

The A’s offense has benefited from the acquisition of Adam Dunn, who has homered twice since the Aug. 31 deadline for postseason eligibility. If Dunn continues to swing a hot bat, it could make the difference in whether or not the Athletics win the West or head off to a one-game playoff. The absence of Yoenis Cespedes, swapped at the July 31 trading deadline to Boston, has been felt and is cited by many of the sport’s observers as a prime reason for the sagging A’s offense of late.

This weekend, Oakland needs to take two out of three games at the very least. The A’s have lost six of their last seven games, one of the reasons their 4-game lead in the AL West disappeared.

Oakland hopes to get back on track with Jeff Samardzija (4-4) on the mound in Friday’s series opener. One player who probably doesn’t mind is Carter, who is 5 for 12 with two home runs and two doubles this season against the A’s righthander.

The good news for Oakland is that the Astros will go with Brett Oberholtzer (4-10), who was hammered for seven runs in 4 1/3 innings in his last start. But if the Astros prevail this weekend, the A’s have no choice but to start looking at how to approach that one-game playoff.