With the Toffees having been forced into their first managerial change in 11 years - on the back of David Moyes' defection to Manchester United - those at Goodison Park are entering the unknown.
That, though, should be considered a positive, according to Jagielka.
He believes Martinez - who has been drafted in from Wigan Athletic - will prove to be a positive appointment and is delighted to have been confirmed as club captain for the 2013/14 campaign.
Jagielka said: "There is a bit of uncertainty amongst the lads. You never quite know if you're the new manager's type of player.
"But he mentioned me as his captain when he spoke to the press, so that was nice to hear.
"You never quite know what to expect but all you can do is keep working hard, keep doing what you do best and hope it will be enough to impress the new man.
"I don't know a great deal about the gaffer, but whenever our paths have crossed he always seems to be a really nice guy.
"We don't know how he will do things, but that's all part of being a footballer. Managers just come and go."