Wales's exit from the showpiece is seemingly Scarlets' gain, with the quartet in contention to step out at Parc y Scarlets against a Munster side who also have won their opening four league matches.
But Pivac has hinted he will err on the side of caution.
"There are a lot of things to factor in, like how much game time they've had," he told the BBC.
"We'll get the feelings of the players on where they're at physically, but mentally as well.
"Jake hasn't had a lot of game time and will be itching to go, but we'll see.
"Round five should be a great occasion. Munster-Scarlets games, there's always a good rivalry and we had a game here last year where we played really well for 74 minutes, we were up by a couple of tries and ended up drawing.
"We'd like to go one better, but we know it's going to be a massive effort because they're playing some good rugby at the moment.
"We have been winning but we still haven't put together an 80-minute performance."
To buy tickets for the GUINNESS PRO12 Grand Final click here. Also follow us on Facebook, join the conversation on Twitter, sign up to our YouTube channel for extensive match highlights and sign up for our newsletter for regular updates on the GUINNESS PRO12
63x46.png){kind=logo}