Spence has been placed on the team's injured reserve list having missed the start of the campaign and being placed on the PUP list.
The National Football Post reports that Spence told Pittsburgh's local news sources: "There was frustration at first because I worked so hard to get to this point, all off-season, during spring ball and in camp and now I am back in the same predicament.
"There is some disappointment, some letdown, but there is a reason to rejoice. I beat a lot of odds as some people thought I would never be able to walk again without a brace, never be able to run again without a brace. I did all of that.
"I think unfortunately I just didn't have enough time. I have a sense of comfort knowing that I will be able to play again, hopefully next season."
Spence is a former third-round Draft pick from Miami, having been picked up by the Steelers in 2012.