The Baggies head coach met the press for the first time yesterday and was asked about a host of issues affecting the club.
High on the agenda was the futures of Pereira and Johnstone who both shone in the Premier League last season and have been linked with moves away.
And Ismael admitted he expects both players to leave The Hawthorns.
“It’s not a secret that Sam Johnstone and Matheus Pereira can maybe leave the club,” the Frenchman said. “It’s my expectation that they (will) leave.
“But I don’t need the best players, I need the right players for the position.
“Even if they leave we will find the solution or we will reinvest the money.
“Maybe we have someone in the academy able to take that position.
“My expectation is that we can lose those players.
“It’s clear for everyone in the club, but we must stay focused and prepare for it – if they stay or if they go.
“My focus is on the players who are here and the pre-season.”
With owner Guochuan Lai understood to want to sell the club, fans have been concerned Ismael won’t get the funds generated from the potential sale of Pereira or Johnstone.
Asked directly if he would be given those funds, the 45-year-old said: “Yes but at the minute I need to have an overview, it’s as simple as that.
“Don’t forget that we have a lot of players still under contract with a lot of quality.
“I don’t need to go on the market and buy 10 or 11 players.
“We have time and now is the time to analyse and reflect on what we have in the squad.”