Carl Carmody and Craig Christophers have got OBR off to positive starts with the bat lately and Purcell hopes that trend will continue.
He said OBR would have a strong squad for the game.
HSOB captain Scott Tallott said his team were approaching the fixture as if it were a final.
“We’re just looking to rip in,” he said.
His bowling attack was “nothing that’s going to blast them out of the water” but aimed to restrict and frustrate the opposition.
HSOB have been the most consistent team with the bat, losing the least number of wickets.
David Salmon, who stood out for HSOB when the teams met on February 9, will return to the side.
HSOB knocked over OBR cheaply and bossed that game, but Tallott said he took nothing from that.
“When the heat comes on, they’re a different side,” he said.
Tallott said the importance of adapting to the situation had become more apparent as the competition went along.
With a points format for wickets and runs, he had to make sure HSOB earned as many points as possible, or “starved” the opposition, and that could come down to strategy.
“I enjoy that,” he said.
Kevin Hollis Glass Pirates are in third place and will play bottom-of-the-table Gisborne Boys’ High School.
Pirates captain Dane Thompson said the club were probably playing for pride at this stage of the season but they would go after maximum points against Boys’ High.
Pirates are still in the mix but need a lot to go right from here.
They fielded a depleted side against OBR last week in a fixture they were not originally scheduled to play and OBR took advantage, shooting up to within striking distance of HSOB.
Pirates still have the best net run rate but their fate may be out of their hands.
“This weekend will tell a lot of the story,” Thompson said.
Gisborne Boys’ High School captain Paul Stewart said his team were concentrating on putting some “positive performances out on the park”.
Boys’ High, who nearly pulled off an upset over HSOB last week, have put in credible efforts that haven’t translated into many points.
Jacob Colbert and Josiah Turner have made useful contributions in the middle order.
“We just want to play as positively as we can — play our own game,” Stewart said.
In the Hope Cup, Bollywood Stars High School Old Boys Presidents will play Coastal Ultrasound Horouta, Ngatapa play OBR’s second 11 and Campion College have a bye.