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HOUSTON -- Having dropped consecutive series for the first time since early June, the Houston Astros will open a critical seven-game homestand starting Monday night against the Toronto Blue Jays with an injury-ravaged roster contributing to their slump.

After losing two of three at home to the New York Yankees, the Astros (55-49) were swept in Detroit, bookending a demoralizing 3-2 loss on Saturday night with two blowout losses.

Houston also lost third baseman Luis Valbuena and center fielder Carlos Gomez to right hamstring strains on consecutive days and will learn of the status of utility infielder Marwin Gonzalez on Monday. Gonzalez has been sidelined by hand soreness.

The Astros have lost five of six games and, after clawing to within 2 1/2 games of the Texas Rangers last week, dropped six games behind in their pursuit of the American League West pennant.

The opener against Toronto could be influenced by more roster flux. Right-hander Doug Fister is slated to start but might land on the paternity list in anticipation of the birth of his first child. That situation facilitated the arrival on Sunday of right-hander Joe Musgrove (7-4, 2.74 ERA in the minors this year), who could make his major league debut.

"We're still in a holding pattern," Astros manager A.J. Hinch told MLB.com. "This may be a photo finish for the game tomorrow. Until my phone lights up with a text or a call from (Fister), it's sort of status quo."

Right-hander Marcus Stroman (8-4, 4.92) will get the start for the Blue Jays. Stroman was at his best in July, finishing 2-0 with a 3.71 ERA in five starts, notching 30 strikeouts against four walks in 34 innings.

Stroman is 0-1 with a 15.00 ERA in his career against the Astros, having surrendered five runs, seven hits and one walk with one strikeout in three innings in his lone start against them.

Having assumed the role of staff ace after the offseason departure of left-hander David Price, Stroman has endured an inconsistent year, one that took a positive turn in July when he posted his best numbers to date.

The Blue Jays (59-46) briefly surged into first place in the AL East before dropping their series finale against the Baltimore Orioles 6-2 in 12 innings on Sunday. The loss was their first against the Orioles after a five-game series winning streak and capped a month in which Toronto finished 16-8, its best record in any month this season.

Locked in a battle with the Orioles and Red Sox for the AL East title while also fending off a host of contenders, including the Astros, in the wild-card chase, the Blue Jays have been subject to countless rumors as the trading deadline nears. And while the recent additions of right-hander Joaquin Benoit and outfielder Melvin Upton Jr. are likely to provide a lift, they don't preclude Toronto from doing more.

"To be honest with you, I don't think about it too much," Blue Jays manager John Gibbons told MLB.com of the rampant trade rumors. "We've already made a couple of deals, so you never know. Everybody's rumored to be going here or going there, but you don't hear about anybody out in that room."