I considered it, but right now propane works better for me. You will first need to get the natural gas line to connect to the fitting at the rear of the Blackstone. Lowes has a kit that will get you part of the way there http://www.lowes.com/ProductDisplay?partNumber=63693-40307-700-0819&langId=-1&storeId=10151&productId=4573820&catalogId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1
While some posts I have read say you don't need a regulator, it can't hurt. You may also need a few other fittings to connect the natural gas outlet at your house to the quick connect hose, and to connect the regulator to the fitting at the rear of the Blackstone ( I would disconnect the Blackstone hose and bring it with you to see exactly what you will need besides the fittings in that kit. Once you have that all sorted out, you will have natural gas to the burner, but unfortunately, propane is much richer than NG, so it won't be anywhere near as hot. To address that, you need to drill out the orifice. To get to that, you have to drill out the rivets holding the face of the grill - Dave Tampa has a great description and photos http://www.pizzamaking.com/forum/index.php/topic,26507.msg273659.html#msg273659
The brass piece at red # 1 is the orifice you will need to drill. I would unscrew it and measure the current hole. According to this chart, http://www.hvacredu.net/gas-codes/module2/Gas%20Orifice%20Capacity%20Chart.pdf
A #42 or #43 drill bit should just fit, and a 3/32 drill bit should be too large ( you will want someone with numbered drill bits to loan you the set, you will only need it for a short time). If so, I would drill it to 1/8, then check and see how it works. If it doesn't seem strong enough, go up to a #30. That assumes your NG is 7". If it is different, you might have to go to a 26 or a 24 drill bit. At about 3:20 in this video, he shows the difference in size of the orifice in a LP v. NG orifice.
Make sure you check your connections with soapy water before you hook it up to gas.