Reed publicly acknowledged his right shoulder injury Oct. 17, a few days before the Ravens played Houston and said it could be affecting his play. The Pro Bowl safety played during practices and games after the injury occurred.
The league said he should have been listed on the injury report with a shoulder injury and was fully participating in practice.
The NFL's policy on injury reports states that players with "significant or noteworthy injuries must be listed on the report, even if the player takes all the reps in practice." The rule covers players the team is certain will play in upcoming games.
Reed has played in every game this season. He has 30 tackles, two interceptions -- including a 34-yard return for a touchdown -- and seven passes defensed.
Washington and Buffalo were fined $20,000 each for similar infractions last week.
The Redskins were fined for not properly updating media on quarterback Robert Griffin III's status during a game against Atlanta on Oct. 7. He left with a head injury that turned out to be a mild concussion.
The Bills failed to list defensive end Mario Williams on the injury report while he was being treated for a sprained left wrist. Williams said on Oct. 3 that the wrist had been bothering him for weeks and limiting his play.
Vikings tight end John Carlson missed Minnesota's game against Tampa Bay on Thursday night because of concussion-like symptoms that appeared to result from Johnson's block during a punt.
Detroit cornerback Alphonso Smith was fined $15,750 on Friday for his horse-collar tackle on Chicago wide receiver Brandon Marshall in the Lions' loss Monday night. Smith was called for a penalty, which helped put the Bears in field-goal range. Marshall and fellow Bears receiver Earl Bennett were also fined $10,500 by the league for wearing orange cleats, a violation of the NFL's uniform policy.
Several other players were fined $7,875 by the league for various penalties, including St. Louis cornerback Cortland Finnegan, who grabbed the facemask of Green Bay's Jordy Nelson on a tackle last weekend that also drew a call for unnecessary roughness.
Carolina's Charles Godfrey was also docked for his low block on Dallas center Phil Costa, who was carted off the field. Panthers coach Ron Rivera signaled for trainers to tend to the Cowboys player immediately after he went down following Miles Austin's fumble. Godfrey received a personal foul penalty.
Information from The Associated Press was used in this report.