Washington (2-0) can match its best start since 2005 with a win at home vs. Buffalo (1-1) on Sunday.
Thomas caught six passes for 65 yards in the first two games; three of those receptions resulted in first downs.
Thomas has been Washington's best tight end as a combination of blocker and pass-catcher. But he missed 11 games two years ago with a hamstring injury and then a torn ACL in his left knee. He missed four games last season because of various injuries.
"It's hard for us just because we know how dynamic he's been," Washington coach Ron Rivera said. "When you lose guys like that, that are productive contributors, the other guys have got to pick up. We like the other guys."
Washington still has veteran tight end John Bates, known more for his run blocking, and second-year Cole Turner, known more for his receiving. Both, however, are able to handle the other aspects of the position.
Both have three catches for a combined 84 yards.
Washington's fourth tight end, Curtis Hodges, has been inactive the first two games. As an undrafted free agent in 2022, Hodges was on injured reserve last season because of a thigh injury.