SEATTLE -- Two teams heading in different directions take the field for a three-game interleague series when the Seattle Mariners host the St. Louis Cardinals beginning Friday.

St. Louis appears ready to make a move in the National League Central, while Seattle could be falling out of the race in the American League West.

The Cardinals (38-33) went into Thursday's off day on a high, having swept the division-leading Cubs to pull closer -- but still not close -- in the Central standings. St. Louis, which is nine games behind Chicago, has a new-found confidence that it can make a push and challenge the Cubs for the Central pennant.

More from FoxSports

"I don't think there's anybody in here who doesn't think we can compete with them or the Pirates," Cardinals first baseman Brandon Moss told MLB.com after Wednesday's win.

If St. Louis fans aren't over-the-moon confident about the Cardinals' chances of getting back in the division race, it might have to do with the fact that St. Louis lost all five of its games against AL West competition leading up to the Cubs series.

This time around, though, the Cardinals face an AL West opponent that is in a freefall. Thursday's loss left Seattle at 36-37, marking the first time since April 23 -- at 8-9 -- that the Mariners were below .500. Seattle enters Friday's game on a six-game losing streak -- the Mariners' longest skid of the season -- and 11 games behind Texas.

Seattle's slump has been all about pitching. The team's rotation has been plagued by injuries, with two starters (Felix Hernandez and Wade Miley) on the disabled list and a third (Taijuan Walker) nursing a sore ankle that will cause him to skip Friday's start. Wade LeBlanc, acquired from the Blue Jays on Wednesday, is expected to fill in for Walker on Friday. LeBlanc marks the seventh different Mariners' starter in a span of seven games -- none of those starters is named Felix Hernandez, who has been out since late May.

Seattle's starting pitching woes found new depths Thursday, when scheduled starter Adrian Sampson, a recent Triple-A call-up to fill the Mariners' ever-widening void, suffered an injury while throwing his warm-up pitches in the bottom of the first inning at Detroit. Reliever Vidal Nuno became the starter and Seattle ended up using six other pitchers in the 10-inning loss to the Tigers, leaving the bullpen in shambles heading into the St. Louis series.

"We're a trainwreck," manager Scott Servais told MLB.com. "We'll have to figure that out."

The only good news to come out of Detroit was Servais telling reporters that Miley should be back by Tuesday to return to the starting rotation. Until then, the Mariners will try to patch together enough healthy arms to get through the weekend series with St. Louis.

The Cardinals open the series with 24-year-old right-hander Carlos Martinez (7-5, 3.17 ERA). Over his past four starts, Martinez is 3-0 with a 1.23 ERA.