Rome is usually safe, except....

You could probably check the schedules. Similar to seeing if your team is playing the Oakland Raiders... they've had their bouts of violence.

http://rome.eventful.com/venues/stadio-olimpico-/V0-001-000369977-0

http://www.triphobo.com/rome-italy

You're overreacting. For every one incident like this there are literally hundreds of other matches where nothing noteworthy happens. Every single team has their share of troublemakers, predicting when and where trouble might happen is like predicting the weather.
Go with the flow. If stuff like this didn't happen from time to time the world would be a boring place. If you happen to be in the wrong place at the wrong time you'll have a story to tell your gandkids.

Soccer travel consumes a lot of my free time, and I have seen and been in the middle of trouble like this in Amsterdam, Mexico City, Basel, East Rutherford, Philly, Newark, Toronto, Anaheim and lived to tell about it. It grows hair on your chest:)

Calm down, Michael S. I hardly think it's "overreacting" to try to gather information in advance. Overreacting would be deciding not to travel at all for this reason. I would just like to know if the police will be anticipating any trouble in advance, as that might be a day to go to less crowded sites. Forewarned is forearmed.

I would just like to know if the police will be anticipating any
trouble in advance

The police always anticipate trouble. The Rome police have riot squads deployed for every single match. 99% of time they are never needed. Once in a blue moon things get out of control, it's not something that can be predicted. If it's something that can ruin you vacation the simple solution is to travel off-(soccer)season: Late May-Late August.

Roberto, thanks for your link. That's very helpful.

This is hilarious. Some clever Romans have responded to the recent ISIS threats against Rome by saying that the Dutch soccer fans beat them to it.

http://www.washingtonpost.com/blogs/worldviews/wp/2015/02/20/the-islamic-state-threatens-to-come-to-rome-italians-respond-with-travel-advice/

First time in Rome last summer, came in on the plane and were taking the metro to the place we were staying. Changing trains, we had our bags and started to board the car when the doors opened. There was a couple with a baby in front of us, we assumed they were trying to get out. We moved left, they moved left, we moved right, they moved right, then I realized something was going on. We pushed through them just before the doors closed, they got out just in time and walked away. My wife's shoulder bag was slightly unzipped. It was pretty unnerving for our welcome to Rome. After that, no problems, but we were a little more alert the rest of the trip.

Michael you are being silly. This was a championship soccer game not a scheduled one, and you could no more predict it than predict your very own Seattle 2014 Superbowl riot. Further, most of the city would not have known anything was even happening.