The pass-rusher and receiver can both be activated at any time and will likely be eased into camp.
Hopkins revealed last month he had shoulder ligaments torn off the bone during the Texans' playoff loss to the Indianapolis Colts. The 27-year-old didn't miss a start in 2018, finishing with 115 receptions, 1,572 receiving yards, and 11 touchdowns.
Watt, 30, underwent a minor knee procedure in January after accruing 16 sacks and a league-leading seven forced fumbles last year.
The Texans are likely being cautious with their two stars and neither player is believed to be in jeopardy of missing Week 1.