How to protect your portfolio from the Greek crisis

Traders work on the floor of the New York Stock Exchange.
Lucas Jackson | Reuters

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U.S. investors braced themselves for a jump in volatility as Greece rejected a bailout in a popular vote, deepening a currency crisis in Europe and adding to the turmoil that is weighing on the global economy.

The CBOE Volatility Index—the market's fear gauge—closed at a tame 17 level on Friday, exactly where it started 2015. Watch for the measure of bearish options activity to explode this week as investors buy put options to hedge a future decline in their portfolios.

If buying put options is not your game, there is one ETF which dependably goes up when the VIX surges. That is the iShares 20+ year Treasury Bond ETF and it should be bought by investors that believe the U.S. stock market volatility from this European contagion will last beyond Monday's trading.

In search of other plays, CNBC Pro used the quantitative tool Kensho to see which assets performed during another banking crisis overseas: the Cyprus bank holiday of almost two weeks in 2013.

During that crisis, gold traded higher by 1 percent, according to Kensho. The Dollar Index added 1 percent as well. Two popular ETFs to play those trades are the SPDR Gold Shares and the PowerShares DB Dollar Index Bullish Fund respectively.

Read More Europe on a 'collision' course

For those with a little more risk tolerance, there is an opportunity to go on the offensive. There are some U.S. ETFs that track the equity markets of countries in Europe that could fall this week as fears rise of a spreading contagion to other countries in the region, like Spain.

"The key is political contagion. Will developments in Greece provide momentum for Podemos in Spain, and non-centrist forces in Italy, France, etc.? This is the big question. We are not sure," wrote Nomura's Jens Nordvig.

An investor could buy put options on the iShares MSCI Spain Capped ETF, the iShares MSCI Italy Capped ETF, and the iShares MSCI France ETF.

Read More Greece: After the big No, what next?

Finally, there's one risky, but interesting strategy going around that calls for one to buy the EUR-USD on the notion that short-covering will cause it to rebound this week.

--With reporting by Deirdre Bosa