The 27-year-old Scotland international returned to Wearside after undergoing a scan on the ankle he damaged in Friday night's 1-0 Euro 2016 victory over the Republic of Ireland, and was therefore unavailable for the 3-1 friendly defeat by England four days later.
However, Black Cats head coach Gus Poyet has confirmed that his worst fears proved unfounded and he expects to have his first-choice frontman available at the weekend.
Poyet told the club's official website, www.safc.com: "Steven is okay - it was not nice at all watching the game and seeing Fletch coming off.
"Naturally as human beings, we always think the worst, but we got in contact straight away with him and the Scottish medical staff, who were very good.
"They sent him back to us and we have done everything possible, so I will say I am 100 per cent sure he will play on Saturday."
Source : PA
Source: PA