This was Shavers 3rd elevation as well and he reverted back to the practice squad on Monday...no waivers process required.
White is eligible for one more elevation and I would imagine he will back up Trubisky on Sunday
I believe you can elevate a PS player up to 3 times in the regular season. The next time (#4) they would have to be added to the 53 man roster to make an appearance. Unlimited elevations during the post season.