Carroll said Tuesday on 710 ESPN Seattle that Lockett suffered a serious shin bruise that required immediate treatment. Carroll did not indicate whether Lockett needed surgery.
He said later Tuesday at the Seahawks' facility that the plan is for Lockett to stay another night at the hospital due to the injury, but he thinks Lockett won't miss any games. The Seahawks have a bye in Week 11.
"He'll be there again tonight just for precautionary reasons," Carroll said. "He's better than he was yesterday, and our people think he's going to be fine to play. He'll need the rest of this week to make sure that everything goes away, but he should be fine to play next week."
Carroll said Lockett is staying in the hospital to make sure there are no problems with the swelling caused by the contusion.
Lockett suffered the injury in the fourth quarter of Monday's 27-24 overtime victory over the San Francisco 49ers, though Carroll did not know exactly when or how Lockett got hurt. He did not play in overtime and was out of the stadium, getting examined, when Carroll's postgame news conference began.
Carroll said Tuesday that he is confident that Lockett will recover from the injury and be fine long-term.
Lockett is the Seahawks' leader in receptions (62), receiving yards (793) and touchdown catches (six). The fifth-year receiver is tied for fourth in the NFL in receptions and is fifth in receiving yards.
Carroll said tight end Luke Willson suffered a "legit" hamstring injury on Monday, his preferred way of describing injuries that are severe enough to force a player to miss time.
"It showed up in the MRI testing of it, so it might be a couple weeks for him. We'll have to wait and see," Carroll said.
The Seahawks have only two true tight ends on their 53-man roster in Willson and Jacob Hollister, who has emerged as a receiving threat with three touchdowns in the past two games. Seattle also uses backup tackle George Fant in a de facto tight end role.
Carroll said veteran tight end Ed Dickson was close to being activated over the weekend and is "ready to go" after spending the first 10 weeks of the season on injured reserve following knee surgery.
"Fortunately, if Luke is unable to play, then we would like to think we can go right to Ed and get him rolling," Carroll said.
ESPN's Brady Henderson contributed to this report.