Turkey would have to be stupid to get involved so heavily. I think they are already deeply regretting the role they had already played so far after Assad all by gift wrapped control of neighbouring areas to Kurdish rebels. During the early stages of the civil war, Turkey was almost gleeful in its support of the rebels, but now, they seem to have gone very quiet of late, with even reports that large amounts of Iranian arms are making their way to government forces via Turkey.
If Turkey does spend in actual combat units to fight against government forces in Syria, I fully expect the Syrians to misplace many of those Igla MANPADS as well as a host of other stuff any terrorist would find very useful in Kurdish controlled areas bordering Turkey. If Turkish involvement looks like it is going to bring about the imminent collapse of Assad's regime, I would not at all be surprised if chemical weapons go walkers inside Kurdish controlled areas as a last parting gift from Assad.
Even the sole superpower America cannot escape blowback from their military adventures half way around the world. For Turkey, the blowback would be far swifter and much more deadly.
I think Turkey misjudged the situation at first, thinking Assad was badly weakened and about to fall with little he could do in response, but they seemed to have somehow forgotten about the Kurdish card, and I think Assad was very clever in playing that card just enough to annoy and worry Turkey without screwing with them so much that it might force Turkey to step in directly. Think if it as a shot across Turkey's bow and a reminder that even though conventionally, the Turkish military could tip the tide, there are things Assad could do before he is taken out that would cause Turkey massive problems for years and decades a to come.
In addition, I think Turkey is looking at the mass gathering of extremist Islamic militant and terrorist groups inside Syria would growing alarm and concern. It was all fun and games when they were just playing puppet master with Syrian rebels who the Turks could relate to and probably think they could easily manipulate or control after Assad is gone to bring the new Syria firmly under Turkish influence. But now they have a friends reunited convention of the most extreme and dangerous Islamic extremists and terrorists in the world going on right across the boarder, and I think the Turks are getting increasingly concerned about what that will mean for them and their own national security if and when Assad falls and those career jihadists start looking for their next adventure after looting the national armouries of Syria.
Turkey wants to rejoin the big leagues, but seemed to have been out of the game too long in that they have forgotten the number one rule of how to be a regional superpower - don't sh!t where you live.
Even a hostile neighbouring government is preferable to chaos and anarchy right on your boarders, and I think Turkey is slowly relearning that important rule. I just hope it is not a very costly lesson for them to learn.