Marvel EIC teased an upcoming announcement regarding Greg Pak in his latest My Cup O’ Joe column:
Spidey616 asks: It can’t be true that writer Greg Pak is leaving Skaar: Son of Hulk with issue #13 when the title is retitled simply Son of Hulk! Is it? Is this truly the end of Skaar for Pak, or is it far from over?
JQ: Rest easy Pak fans! There’s a MAJOR MAJOR announcement coming up for Hulk and Greg Pak that has a LOT to do with Hulk #600! (See how important that single issue is going to be?!)
Marvel has posted six colored pages from the “Planet Skaar Prologue,” written by Greg Pak with art by Dan Panosian. 

“Skaar” #10, written by Greg Pak with pencils by Ron Lim, hits comic book stores on April 29.