Fitzwater, a deadline day arrival from Albion, has impressed in five outings for the Saddlers and netted his first goal in Saturday's narrow 2-1 loss to Blackburn.
Out of contract with the Baggies in the summer, it is not yet known if the 20-year-old will be offered a new deal at The Hawthorns. But even if he is, Whitney is refusing to rule out another loan.
And with fellow defenders Liam Kinsella, Nicky Devlin, Jon Guthrie, Kory Roberts and Luke Leahy already contracted for next year, the boss believes strong foundations are being laid.
"Jack is player we’re looking at long term," Whitney said.
"He is out of contract in the summer. But we have also spoken about extending the loan into next season as well.
"I’d like to get the group together, because the more we work together, the more we’ll reap the benefits going into pre-season and next season.
"It’s also nice that in midfield and up front we have got Kieron (Morris), Ama (Bakayoko), George (Dobson), Maz (Kouhyar) all contracted.
"We have got that young, vibrant group who we want to play together and really get that understanding.
"That has been a main aim for myself and the board. A lot has been said about loans.
"But long term, we want permanent additions. Each game we play now with that unit in place can only be a good thing moving forward."
Whitney believes it's particularly important for a back four to play together regularly if they are to improve and regularly keep clean sheets.
"As a defence, you can't beat playing together," the boss continued.
"Training together is great. But to cope with the expectancy and intensity of a match day, you need to play together on a regular basis.
"That is where you build that understanding."
Whitney is also pleased with the way youngster Roberts is pushing Fitzwater and Guthrie for a first-team place.
"Kory is getting stronger all the time," he added.
"I watched Kory for the under-23s last week and he was outstanding. He really captained the team and you can see a maturity because he has had those first-team games."