Jeremy Fowler of ESPN reported the news.
Lacy, 27, is 2-for-2 in passing contractually obligated weigh-ins that were put into his one-year contract with the Seahawks. He weighed in at 253 pounds on May 15 against a 255-pound weight limit, and the team has five more weigh-ins scheduled.
"Challenges. As a competitor, you want to be challenged," Lacy said of the weigh-ins, per Sheil Kapadia of ESPN.com. "So it's a positive challenge. At the end of the day, it helps me personally, too, so why not?
"I have a great support group behind me from coaches to players to the nutrition team. So everybody's positive, which helps me because I know I have a group of people behind me pushing me, so it's all working out, it's all going great. I've just got to continue to go that way."
Lacy was listed at 234 pounds last season with the Green Bay Packers. He rushed for a career-low 360 yards and was limited to five games due to injuries. After beginning his career with consecutive 1,000-yard seasons, Lacy has been held under that total each of the last two years.
The Seahawks are hoping to have Lacy at 245 pounds or less during the regular season. He's expected to compete with Thomas Rawls and C.J. Prosise for carries in what will likely be a timeshare going into training camp.
No Seahawk rushed for more than 469 yards last season.