TEMPE, Ariz. -- A blood test Thursday revealed that Arizona Cardinals wide receiver John Brown carries the sickle-cell trait and has been listed as doubtful for Sunday's game, coach Bruce Arians said Friday.
Brown experienced leg pain before Monday night's win over the New York Jets and was diagnosed with sore hamstrings after the game. But an MRI this week didn't reveal any issues with his hamstrings, which led to the blood test.
"We're investigating on how to help him get better as fast as possible," Arians said.
According to the Centers for Disease Control and Prevention, sickle-cell trait is the result of one inherited sickle-cell gene and one normal gene. Those with the sickle-cell trait "usually" don't exhibit symptoms of sickle-cell disease. In rare cases, however, "people with SCT might experience complications of SCD, such as pain crises."
According to the CDC's website, those with sickle-cell trait are "more likely" to experience muscle breakdown when doing "intense exercise" than those who don't have the trait.
Brown was plagued with hamstring issues for the last 2½ months of last season, which Arians said is likely related to the sickle-cell trait diagnosis.
Arians thinks Brown is relieved to discover a potential reason for this pain.
"I think he's very happy that he found out why his legs are hurting so bad," Arians said.