Romo hid the hand from reporters at the Cowboys' practice facility but said the swelling has gone down "a little bit" since Dallas' 20-7 loss to Philadelphia, the (Fort Worth, Texas) Star-Telegram reported.
Romo smashed the hand on the helmet of Philadelphia defensive end Jason Babin on the Cowboys' fourth offensive play. He was replaced by Stephen McGee, who went 24-of-38 for 182 yards with a touchdown and no interceptions.
Cowboys head Coach Jason Garrett told reporters X-rays were negative and Romo's hand "looks like it's getting better."
"It looks like the swelling is going down, and we're hopeful that he can practice on Wednesday," Garrett said.
The Cowboys meet the New York Giants Sunday, with the NFC East title and a post-season berth going to the winner.