Morrow didn't return to Monday night's 5-4 victory over Colorado after he was gimpy coming off the ice during a shift change in the second period. He was evaluated Tuesday.
Coach Dave Tippett said the injury wasn't as bad as feared, but that the Stars wanted to be cautious to make sure it doesn't become a long-term problem.
While Morrow likely won't play Wednesday night at home against Nashville, right wing Jere Lethinen could be back in the lineup after missing three games with a sore leg.
Morrow scored twice in the final three minutes of the first period Monday to help Dallas forge a 2-2 tie.