Joao Plata (eight goals) and Alvaro Saborio (six) have led the goalscoring for Real Salt Lake, but were the only two forwards on the board this season before Olmes Garcia's brace against the Montreal Impact.
Real Salt Lake general manager Garth Lagerwey said he and coach Cassar wanted to avoid turning to the transfer market.
"[We] have both been out looking at some options. Our preference remains, as I've expressed repeatedly, to keep our team," he said.
"We think these guys have earned it. We think we have a good, veteran group."
The Red Bulls sit fifth in the East but are winless in two matches and will be relying on the league's top goalscorer Bradley Wright-Phillips (17 goals).
A pair of the Eastern Conference's top sides also do battle on Wednesday as DC United host Toronto.
While DC are on a three-match winning league run, Toronto are winless in their past three outings.
The New England Revolution are out to end a seven-match losing run in all competitions when they host the Colorado Rapids.
The Vancouver Whitecaps could climb into the top five in the West with a victory at the Chicago Fire.