Do you think Grimmjow is back? I honestly don't know.
The blade that was shown at the end DOES MATCH with Grimmjow's, however, it also matches with Grandpa his zanpakutou.
WARNING SPOILERS FOR ANIME WATCHERS (although it stopped)
http://i996.mangareader.net/bleach/5...ch-3442141.jpg
http://i3.mangareader.net/bleach/281/bleach-2407129.jpg
Also please refrain from posting bashing posts.