Ryan Clark, Pittsburgh Steelers Safety, Sits Out Season Opener, Launches Sickle Cell Campaign

FILE - In this file photo taken Nov. 13, 2011, Pittsburgh Steelers safety Ryan Clark watches from the sidelines the first hal
FILE - In this file photo taken Nov. 13, 2011, Pittsburgh Steelers safety Ryan Clark watches from the sidelines the first half of an NFL football game against the Cincinnati Bengals in Cincinnati. Clark wants to play in Denver on Sunday, Jan. 8, 2012, against the Broncos in the wild card round, however, Steelers coach Mike Tomlin is holding Clark out of the lineup as a precaution due to a sickle-cell trait that becomes aggravated when playing at higher elevations. (AP Photo/Tony Tribble, File)

The Pittsburgh Steelers will be one man short when they take the field for their season opener against the Denver Broncos this Sunday. Safety Ryan Clark is expected to sit out the first game in an effort to ward off symptoms of sickle cell, which have been known to flare up at Denver's low-oxygen, high-altitude Mile High Stadium.

In fact, Clark nearly died the last time he played there, suffering a life-threatening "crisis" that ultimately cost him his gall bladder and his spleen.

But while he's sitting out for Sunday's game, Clark is standing up in the fight against sickle cell disease, announcing the launch of Ryan Clark’s Cure League during a press conference Tuesday.

The initiative aims to research and find a cure for the disease, a plight that is not only motivated by his own battle with the trait, but by the loss of his sister-in-law from it at the age of 27.

“Sickle cell is fatal,” Clark told CBS Pittsburgh. “My sister-in-law died at the age of 27, the year after I had my crisis. So this is important to me.”

According to the organizations website, Ryan Clark's Cure League, a partnership with the University of Pittsburgh and UPMC, raises money to fund sickle cell disease research, support patient care programs, and increase public awareness about the genetic blood disorder that is said to affect about one in 500 African-Americans in the U.S.

In this month's issue of WebMD the Magazine, actor Larenz Tate championed greater awareness of sickle cell disease and the importance of screening for the trait, which causes red blood cells to resemble sickles or crescents that can result in reduced blood flow, chronic fatigue and intense pain.

Alongside his brothers, Tate launched a similar initiative in 2004 to help raise awareness and research funding for children of color living with sickle cell anemia and sickle cell disease.