According to The Big Lead when you watch the #3 or #4 Fox broadcast team during the 2016 – 2017 NFL season you will notice the absence of Tony Siragusa on the sidelines.
While for most, this will not make any difference to their viewing experience. The role of the sideline reporter has been debated forever. We all know the practical and business reasons why they exist. I suspect Fox has not gotten the type of response they were hoping for, having the former lineman serve as more of an additional color commentator from the sideline.
Another reason would be the massive budget cuts Fox Sports is making. Considering how long Siragusa has been around he probably made a hefty salary to just watch games from the field and now that salary is off the books.