The team fears Smith has a torn triceps, and he will undergo further tests Monday. However, the Steelers are operating under the assumption that Smith will be out for the season, according to the source.
Coach Mike Tomlin said he didn't know the extent of Woodley's injury, but didn't sound optimistic about Smith.
"Not good, but such is life in the National Football League," Tomlin said. "We will adapt and hopefully overcome it."
The Associated Press contributed to this report.