The 19-year old Tottenham midfielder, who joined the Fire on loan in March, has been sidelined since breaking a bone in his foot after impressing on trial with the MLS side.
"He might be on the bench," Yallop said.
"I obviously want to get Grant back playing with us, like he was in preseason. He has looked good, and although he's only had a couple of days of full practice, he was doing a lot at Tottenham before he came over.
"I just didn't want to risk him right away with our group."
Ward admitted he was ready to step into the MLS cauldron as the seventh-placed Fire look to make it three wins in a row.
"I'm just taking it one day at a time to make sure that I'm ready," Ward said. "And if I'm ready, then maybe I can be involved. I feel ready, and I feel like I could play."
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