Did Sauron imprison the Moria Balrog?

[CAB]

In Appendix A of the Lord of the Rings it says that the Balrog of Moria was “roused from sleep” or released from prison by the Dwarves. It also states that the Balrog had been there since the end of the First Age. I can think of no other examples of someone sleeping for over 5000 years in the history of Middle Earth. This option seems very unlikely to me, so I am going to focus on imprisonment.

Who could be found in this part of Middle Earth early in the Second Age capable of imprisoning the Balrog? Galadriel? Maybe, but she and Celeborn didn’t seem to be aware of what was the evil force in Moria when the Fellowship came to Lorien. Who else? I would guess only Sauron.

Here is the scenario I would like to propose. The Balrog escapes from Morgoth’s defeat at the end of the First Age, while Sauron is captured. Later, Sauron escapes and comes further east with thoughts of becoming the new Dark Lord. The logical thing for him to do is search for the strongest help available, the Balrog, who he finds hiding under the Misty Mountains. The Balrog refuses to accept Sauron as it’s new master. It may be afraid of the Valar, want to be it’s own boss, or have another reason. Sauron’s reaction isn’t to kill the Balrog, but to imprison it. This would seem to be a much more cruel punishment, a fitting revenge for someone like Sauron.

Much later, the Balrog is released by the Dwarves. It kills many of the inhabitants of Moria and takes possession of the place as it’s new home. Why doesn’t it leave Moria and seek vengeance against Sauron? Because it is scared. It doesn’t want to be stuck in a stone box for another few thousand years. The Balrog would rather stay in a strong place (probably much like the Witch King in Angmar) so it can defend itself against Sauron.

c. 2480 Orcs begin to make secret strongholds in the Misty Mountains so as to bar all the passes into Eriador. Sauron begins to people Moria with his creatures. - Tale of Years, The Return of the King

Some would argue that this quote proves that Sauron was in control of the inhabitants of Moria. I would disagree. If he was, why did the attacks on Lorien during the War of the Rings at the end of the Third Age come only from Dol Guldur? Also, why wasn’t there a stronger force stationed at Moria? It seems to be especially strong in a military sense. It has access to both sides of the mountains, is close to Lorien, and controls the Redhorn pass. Also, it all but unconquerable from without. Sauron himself, at the height of his power in the Second Age was unable to take Moria. I would guess that the Orcs that Sauron sent to Moria were quickly converted by the Balrog to it’s own cause.

There is also the Balrog’s fight with Gandalf. Apparently Gandalf took the upper hand during the fight and the Balrog fled from him. It ran and ran from the roots of the mountains all the way up the Endless Stair to the peak of Silvertine. It fled all this way, got outside where it could escape and did what? It turned and fought Gandalf to the death?! Does that make any sense? I would guess that it was so afraid of leaving it’s stronghold and becoming vulnerable to Sauron, that it was forced to face Gandalf again. Gandalf probably fully expected the Balrog to jump or fly off (I am not trying to start that debate) at this point.

I have a few other points but this is becoming a long post, so I will leave it at that for now.