The 24-year-old winger tweeted on Monday: "Had enough of been (sic) treated like a kid! #fedup just want to play football."
Compton, who has been advised by Whittingham to consider a loan spell away from the club, later removed the post.
"Players sometimes feel if they are not in the squad they are out of it. Well, that's not the case," the Pompey chief told the Portsmouth News.
"You need everybody all the time and they have to keep doing the right things all the time, because at one stage or other they will be on the pitch and will be the difference.
"Another time Jack will be on the bench, I'll look around, look at him and get him on. He won't be the only one. He was going to Plymouth for some games but that didn't quite go through - it didn't come off for him, but he's still very much part of things."
- Sports & Recreation