The welsh side dropped to a season-low fifth spot last weekend after a narrow 19-16 defeat to league-leaders Glasgow Warriors, with the likes of Rhys Webb and Dan Biggar on international duty with Wales.
And next up Ospreys welcome play-off rivals Leinster to the Liberty Stadium on Friday evening, before Munster are in town eight days later, with both encounters likely to be key in the race for the GUINNESS PRO12 play-offs.
But 28-year-old Spratt, who played 80 minutes for the Swansea outfit in last weekend's defeat, is adamant Ospreys have more than enough in the locker to come through the crunch clashes with victories.
"These are vital games, especially with the Welsh boys being away. It's up to us to step up to fill the void," he told the South Wales Evening Post.
"With the experience here and the youth coming through, I think we've got a really good chance.
"The boys stepping up to the plate have definitely got that power and ability to go forward and get the victory that we need.
"Defensively there are definitely some areas to improve on after Glasgow. Leinster were unfortunate against the Dragons last week and I'm sure they want to put that right.
"They haven't won four league titles without good reason. When they lose players they have experienced boys coming in to replace them, so even without the internationals it will be a tough test."
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