Dyche was axed last week by Forest and eventually replaced by Vitor Pereira.
Jenas told the Wildcards Podcast: “I’m surprised if I’m honest with you. I am very surprised.
“I think that it’s quite clear that under the owner Marinakis, it’s a volatile environment for managers to go to.
“I think there are like two things here. Do you know any new managers that he’s going to be trying to attract?
“You know it’s one of those jobs that you know you’re not going to be there for a long time, almost no matter what.
“It kind of shows the ruthless nature that the owner’s working under.
“Which can’t be nice for anybody in that environment.
“Ok, you know, a lot of people say well he adopted a team that finished like fifth/sixth in the Premier League and was in Europe but essentially what Sean Dyche walked into was chaos he walked into a situation where um you know the previous manager Nuno Espirito Santo wasn’t happy they were losing games.
"They were on a downward spiral already down there in the league earlier on and you know that whole breakup with Nuno wasn’t pretty it was very public in terms of the way that it was handled.
“I felt he came in and he’s done a decent enough job."