Three Army Combat Brigades?

There were initial rumors that we'd send 35,000 troops to Afghanistan, including 3 Army combat brigades and a Marine regimental combat team or expeditionary brigade. I assumed these would be formed combat units and that any brigades sent as trainers would be in addition to the combat brigades.

When the decision to send 30,000 troops came out, I assumed that this must mean only 2 Army combat brigades in the mix.

But stories came out that the president's decision to send 30,000 might end up being 35,000. So what would that mean for combat brigades?

Now this story, noting the difficulty the military will have getting equipment sent and facilities to receive these troops over the next six months, also states:

The Marines will send a Regimental Combat Team from Camp Lejeune, N.C. to Helmand province. Most of the remaining forces will travel to Kandahar province, the birthplace of the Taliban. Army officials said that next week they'd begin notifying the three Army brigades that will be sent.

So does this mean three Army brigades sent as units plus another brigade broken up for training teams? Or does this mean that trainers will come from one of these three brigades? And was my initial assumption of three formed combat brigades in error, for that matter.

Perhaps it is just my incorrect assumption that when you speak of brigades/regiments that means formed units sent to fight as units. Perhaps the stories all along just meant units sent regardless of what they look like once there.