Evaluating Thomas Harper's chances to return from concussion vs the Rams
With a review of Lions concussion data over the past 2 seasons
What are Thomas Harper’s chances of playing on Sunday vs the Rams - 10 days following his concussion? His 2 limited practices to start the week have him trending in, as it means he is moving smoothly through the 5-phase concussion protocol. If he plays, that would make him just the third Lion in the past 2 seasons to play within 10 days after a concussion.
While the percentage of concussed Lions to play within 10 days is low, diving into each case demonstrates why a Harper return in that timeframe would be unsurprising… and even somewhat expected.
Here is the Lions return-to-play data over the past 2 seasons (as of Dec 12, 2025).
Days to return-to-play following concussion
9 - Hendon Hooker (2024)
10 - Alim McNeill (2024)
11 - Trevor Nowaske (2024)
15 - Alex Anzalone (2024)
18 - Terrion Arnold (2025)
21 - Brian Branch (2024)
56 - Khalil Dorsey (2025)
indefinite - Morice Norris (2025)
never - Antoine Green (2024)
pending - Thomas Harper (2025)
Maybe the most interesting takeaway is that no Lion in the past 2 seasons has returned to play in under 9 days. The caveat is that there is often a delay in return due to scheduling quirks or unrelated factors.
Here are the detailed breakdowns of the concussions:
2025 season
Terrion Arnold (November 9)
return-to-play = 18 days
Arnold took longer to return from the concussion than expected. This seems likely related to the right shoulder injury that threatened his season just a month prior. After his first game back from the concussion, he decided to have shoulder surgery which ended his season.
Khalil Dorsey (September 28)
return-to-play = 56 days
Dorsey had a full practice leading up to the next game which put him firmly on track to return in just 7 days. However, he suffered a wrist injury during the week that landed him on IR.
Morice Norris (August 8)
return-to-play = indefinite
In this preseason game, Norris notably appeared to have a seizure in the immediate seconds of the concussion. Fortunately, he appeared to recover quickly and was back with the team within days. He might have been able to return to play within 2-4 weeks, but he did not make the team and is currently out of the NFL.
Thomas Harper (December 4)
return-to-play = pending
2024 season
Hendon Hooker (August 8)
return-to-play = 9 days
No video here as the moment of injury was uncertain. Hooker played nine days later in the next preseason game.
Antoine Green (August 8)
return-to-play = never
This concussion included a significant neck injury that caused Green to retire from the NFL.
Alex Anzalone (September 15)
return-to-play = 15 days
One of the friendly fire incidents of the 2024 season caused Anzalone to miss one game. He returned to play in 15 days.
Brian Branch (September 22)
return-to-play = 21 days
This was an interesting case. Branch passed through the 5-phase concussion protocol within a few days after the concussion and appeared set to play in the next game in 8 days (Monday Night). However, an illness popped up late in the week, and he ended up missing the game. The missed game may have been due to a combination of illness and the recent concussion.
Many concussion symptoms can be non-specific and vague such as headache, nausea, dizziness, and fatigue. These symptoms show up in many routine illnesses which can make attributing their root cause difficult to impossible.
Despite passing through the concussion protocol, there may have been concern he was still having post-concussion symptoms which would have made sitting him prudent.
Branch very likely would have been ready to go at the 14 day mark, but the bye delayed his return to 21 days.
Alim McNeill (December 5)
return-to-play = 10 days
Officially, the injury was reported as a “head” during the game, not a concussion. McNeill had a suspected TMJ (temporomandibular joint) issue earlier in the year so there was suspicion it could be related to that.
After the game, he was then diagnosed with a concussion. The next Lions game was in 10 days in which he played and unfortunately tore his ACL.
Trevor Nowaske (December 11)
return-to-play = 11 days
Nowaske suffered the concussion during the practice week. He missed one game and returned to play in 11 days.