With trade deadline looming, these MLB series are kind of a big deal

Rare is the July series that can define the course of a season. But with baseball's trade deadline looming, a franchise's self-analysis can change in a hurry. USA TODAY Sports' Jake Lourim examines this week's showdowns that might frame teams' activities — buy, sell or stand pat — come July 31:

Seattle Mariners at Detroit Tigers, Monday-Thursday

At stake for the Mariners: With Robinson Cano showing signs of life — he hit two homers Saturday — the Mariners think a second-half rally is within reach. They were nine games out in the division entering Sunday night and eight back in the wild-card race, but winning games would take care of the wild-card field.

At stake for the Tigers: Detroit's fading starting pitching and weak bullpen are threatening a four-year streak of American League Central titles. The Tigers sit 10½ games behind the red-hot Kansas City Royals and 4½ back in the wild card. Years of depleting the farm system have left them without many prospects to trade, but they could replenish quickly with David Price and Yoenis Cespedes if they decide to sell.

Key matchup: Thursday, Hisashi Iwakuma vs. Price. Iwakuma, after missing 2½ months with a strained back muscle, has won two consecutive starts and could be a key to the Mariners' revival. Meanwhile, the Tigers are 15-4 when Price pitches. But if they lose more ground before Thursday, it could be his last start in a Detroit uniform.

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San Francisco Giants at San Diego Padres, Monday-Wednesday

At stake for the Giants: Staying within shouting distance of the Los Angeles Dodgers — they're just 3½ games out. The Giants are one game out of the wild-card race and might be the most complete team in that mix.

At stake for the Padres: Two wins vs. the Colorado Rockies have San Diego within 9½ games in the West and seven in the wild card. They have been presumed sellers for weeks, but that could change if they win this series before entering another home set vs. the Miami Marlins. After going all in with four offseason trades, the Padres could be hesitant to give up so soon.

Key matchup: Monday, Tim Hudson vs. Ian Kennedy. After a shoulder injury landed him on the 15-day disabled list, Hudson is making his first start since June 26. Kennedy could be on the block if the Padres sell.

Boston Red Sox at Houston Astros, Tuesday-Thursday

At stake for the Red Sox: Boston did not score in its first two games after the break, pushing it eight games back in the division and 7½ back in the wild-card race entering Monday's doubleheader at Anaheim. Houston provides another measuring stick for a Red Sox team that's not out of it but has fallen well short of expectations.

At stake for the Astros: Houston has lost the AL West lead, and the surging Los Angeles Angels aren't helping their cause. Will they add a top starting pitcher, such as Johnny Cueto, at the deadline? Or perhaps another outfielder? It's not as much whether the Astros will buy as it is what. A stocked farm system provides options.

Key matchup: Tuesday, Brian Johnson vs. Vincent Velasquez. Boston's Johnson is making his major league debut against the power-heavy Astros, while Houston continues to struggle finding depth in the rotation.

Toronto Blue Jays at Oakland Athletics, Tuesday-Thursday

At stake for the Blue Jays: Toronto's offense has cooled off, dropping the club to .500 and into a tie for third place in the AL East. If the Blue Jays can stay close, they will try to add a pitcher to help their staff.

At stake for the A's: Likely their last gasp at bona fide contention. It's widely presumed general manager Billy Beane will try to trade players such as Scott Kazmir, Ben Zobrist and Tyler Clippard, though he also could deal some of those impending free agents, keep others and play for now and the future.

Key matchup: Tuesday, Mark Buehrle vs. Kendall Graveman. Buehrle has been the closest thing to an ace the Blue Jays have had this season, and he'll need to continue to pitch well during their playoff hunt. Graveman has dominated since an early trip back to Class AAA, and he'll match up with MVP candidate Josh Donaldson, who went to Toronto in the offseason in exchange for a package that included Graveman.