How serious is Marvin Harrison Jr.’s injury?

The much-anticipated homecoming of Arizona Cardinals wide receiver Marvin Harrison Jr. in Indianapolis took an unfortunate turn on Sunday after the second-year player suffered a concussion that forced him out of the game against the Colts — the same franchise where his legendary father, Marvin Harrison Sr., became an NFL Hall of Famer.

Harrison Jr.’s day ended abruptly late in the second quarter when he hit the back of his head hard on the turf following a 21-yard reception over the middle. The young receiver initially appeared shaken, remaining on the ground for several seconds as medical personnel rushed to his side. He later walked off under his own power but was immediately taken to the team’s blue medical tent for evaluation.

After a brief assessment on the sideline, the Cardinals’ medical staff escorted Harrison to the locker room for further testing. By halftime, the team confirmed what many feared — Harrison had suffered a concussion and would not return for the remainder of the game. Before his exit, he had recorded two receptions for 32 yards, showing flashes of the route-running precision and body control that have made him one of Arizona’s most promising young stars.

The injury came in what was supposed to be a sentimental and symbolic moment for the 22-year-old receiver — his first professional game in Indianapolis, inside Lucas Oil Stadium, where his father built a legendary career with Peyton Manning and helped the Colts capture a Super Bowl title. Earlier in the week, Harrison Jr. had called the matchup “a special game for me, for sure,” noting that stepping onto the same field his father once dominated was a full-circle moment in his football journey. Unfortunately, that moment was cut short by a hard fall that silenced the stadium.

The play in question came on a deep throw from quarterback Jacoby Brissett. Harrison secured the catch but was tackled immediately, with his helmet striking the turf. The crowd, which had shown enthusiasm for the son of their former star, fell silent as he remained on the ground. Trainers quickly intervened, following the league’s concussion protocol procedures.

The Cardinals officially ruled Harrison out just as the third quarter began, stating that he had entered the NFL’s concussion protocol. The extent of his recovery timeline will depend on further evaluations in the coming days. Players diagnosed with concussions must pass a five-step return-to-play process that includes rest, gradual physical activity, and clearance from an independent neurological consultant.

This isn’t the first time Harrison Jr. has faced a concussion. He sustained a similar injury during Week 6 of the 2024 season but returned to action the following week. Still, repeated head injuries remain a concern in a league that continues to emphasize player safety and concussion management.

Before Sunday’s setback, Harrison had been enjoying an encouraging sophomore campaign, showing marked improvement over his rookie season. Through five games, he had accumulated 20 receptions on 32 targets for 306 yards and two touchdowns, averaging 15.3 yards per catch — up from 14.3 yards per reception last year. His 61.2 receiving yards per game had him on pace to potentially surpass the 1,000-yard milestone for the first time in his career.

The Cardinals, already dealing with several offensive injuries this season, will now have to navigate the coming weeks possibly without one of their most dynamic playmakers. His absence could place added pressure on veterans like Hollywood Brown and tight end Trey McBride to shoulder the offensive load while Harrison recovers.

While Sunday’s game carried emotional weight for the Harrison family and fans alike, it also served as a sobering reminder of football’s physical toll. For now, Arizona’s focus shifts from the symbolic to the practical — ensuring their rising star recovers fully and safely.

FAQ: Marvin Harrison Jr.’s Concussion and Injury Update — Cardinals vs. Colts 

1. What happened to Marvin Harrison Jr. during the game against the Colts?
Arizona Cardinals wide receiver Marvin Harrison Jr. suffered a concussion during Sunday’s matchup against the Indianapolis Colts. The injury occurred late in the second quarter after he caught a 21-yard pass over the middle and hit the back of his head hard on the turf during a tackle. He stayed down briefly before walking to the sideline for medical evaluation.

2. Where and when did the incident occur?
The incident happened at Lucas Oil Stadium in Indianapolis on Sunday, October 12, 2025. It was an emotional venue for Harrison Jr., as it marked his first professional game in the city where his father, Marvin Harrison Sr., became a Hall of Fame receiver for the Colts.

3. What was the severity of the injury?
The Cardinals’ medical team diagnosed Harrison Jr. with a concussion after evaluating him in the sideline medical tent and later in the locker room. He was officially ruled out for the rest of the game at halftime. No additional head or neck injuries were reported, and he left the field under his own power.

4. Did Marvin Harrison Jr. have a history of concussions before this?
Yes. Harrison Jr. previously suffered a concussion during Week 6 of the 2024 season. He recovered quickly and returned to play the following week, but this latest head injury raises new concerns about his long-term health and the potential risks of repeat concussions.

5. How did the Arizona Cardinals respond to the injury?
The Cardinals’ coaching staff and medical team followed NFL concussion protocol immediately. Head coach Jonathan Gannon confirmed after the game that Harrison Jr. will enter the league’s mandatory concussion protocol process, which involves a step-by-step recovery and clearance procedure before he can return to play.

6. What is the NFL concussion protocol?
The NFL’s concussion protocol consists of five phases:

1. Rest and recovery – Players avoid physical activity while symptoms subside.

2. Light aerobic exercise – Gradual reintroduction of movement to increase heart rate.

3. Football-specific exercise – Incorporating non-contact drills and position-based work.

4. Club-based non-contact training – Full-speed training without contact.

5. Clearance for full participation – Final medical clearance by both team and independent neurological specialists.

Harrison must pass each stage without symptoms before being cleared to play.

7. How was Harrison Jr. performing before the injury?
Before exiting Sunday’s game, Harrison Jr. had two receptions for 32 yards, including the 21-yard catch that led to his injury. Through five games this season, he had recorded 20 catches for 306 yards and two touchdowns, averaging 15.3 yards per reception — an improvement over his rookie average of 14.3 yards per catch.

8. Why was this game significant for Harrison Jr.?
This was Marvin Harrison Jr.’s first professional appearance in Indianapolis, the same city where his father, Marvin Harrison Sr., became one of the NFL’s all-time greats as a wide receiver for the Colts. The younger Harrison had described the matchup as “special” earlier in the week, viewing it as a symbolic return to his family’s football roots.

9. How long could Harrison Jr. be out?
The length of his recovery depends on how quickly he progresses through the NFL’s concussion protocol. Some players return within a week, while others take longer depending on the severity of symptoms. The Cardinals are expected to monitor his status closely throughout the week before determining his availability for their next game.

10. What impact does his absence have on the Cardinals’ offense?
Losing Harrison Jr. is a significant setback for Arizona’s offensive unit. The young receiver has been one of the team’s emerging deep threats this season. In his absence, the Cardinals will likely rely more heavily on veteran wideout Marquise “Hollywood” Brown and tight end Trey McBride to fill the gap in the passing game.

11. What was the crowd’s reaction in Indianapolis?
The atmosphere at Lucas Oil Stadium grew tense as fans — many of whom still revere Harrison Sr. — watched the younger Harrison stay down after the hit. The crowd applauded respectfully when he stood and walked to the sideline, acknowledging the emotional moment for both the player and the city.

12. How does this affect Harrison Jr.’s potential breakout season?
Before the injury, Harrison Jr. appeared to be on track for a breakout sophomore campaign, averaging over 60 receiving yards per game and positioning himself for a potential 1,000-yard season. Depending on the duration of his recovery, the injury could temporarily stall that momentum.

13. Has the team provided any update since the game ended?
As of postgame Sunday, the Cardinals confirmed only that Harrison had suffered a concussion and would enter protocol. Further updates on his condition and timeline for return are expected later in the week after additional medical evaluations.

14. What precautions will the team take moving forward?
Given his history of concussions, the Cardinals’ medical staff will likely be cautious in managing his recovery. The team may adjust his workload in practice and monitor him for any lingering symptoms before clearing him for full contact.

15. What’s next for Marvin Harrison Jr. and the Cardinals?
The Cardinals will focus on Harrison Jr.’s recovery while preparing for their upcoming schedule. If cleared, he could return within one to two weeks. Until then, the offense will need to adapt without one of its most dynamic playmakers as Arizona continues to fight for position in the NFC West.