The Tannadice outfit lost striker Johnny Russell to a broken leg earlier this week, while Jon Daly is struggling with a knock leaving McNamara short of options in attack.
McNamara admits he may now look at the free agent market in a bid to add some cover to his squad.
"Jon Daly is carrying a knock now so we are low on numbers," McNamara told the Daily Record. "I might look to bring someone in. We'll wait and see.
"We're short of options in certain areas of the team so I'll look at that."