Right now there are two destroyers, three medium-sized amphibs, seven support ships, and an unknown number of submarines operating in the area. If things start to get really troublesome, they might deploy their Black Sea Fleet, which has two cruisers, one destroyer, two frigates, and thirteen corvettes. A number of these ships are armed with the SS-N-22 Sunburn ramjet anti-ship missile. A wave-hugger with a speed in excess of Mach-3, this missile was designed to cripple US carriers and kill just about anything else.
The aircraft carrier Admiral Kuznetzov and its escorts are scheduled to return to the Med before the end of the year.
Turkey is on our side against Assad so Russia might have a hard time moving its forces into the Mediterranean.