(Revolution photo) (Revolution photo)

Clyde Simms, who spent most of his pro career with D.C. United, is retiring because of worsening kidney disease — the same ailment that afflicted NBA stars Alonzo Mourning and Sean Elliott.

Simms, 31, spent the past two seasons with the New England Revolution after seven in Washington.

“I’ve never really talked about this because I always chose the mind-over-matter approach, but my health has gotten to a point where I can no longer do that,” Simms said in a written statement released by the Revolution on Thursday.

Simms was diagnosed with focal segmental glomerulosclerosis during his freshman year in high school. When he began his MLS career, “my kidney function was around 50 percent, and the last three years of my career, it has gotten down to about 20 percent.”

According to Mayo Clinic, FSGS is “a disease in which scar tissue develops on the parts of the kidneys that filter waste out of the blood. FSGS can be caused by a variety of conditions. Without treatment, primary FSGS will usually lead to kidney failure where the only treatment options are dialysis or kidney transplant.”

Mourning, a Georgetown star who played 15 years in the NBA, underwent a transplant in December 2003 and returned to basketball the following season. Elliott had the same procedure three years earlier.

“I fell in love with this sport at a young age and was determined not to let anything stop me,” said Simms, a North Carolina native who played at East Carolina University before joining the Richmond Kickers. “Unfortunately, for the past 10 years I have been dealing with kidney disease and it has become too tough for me to compete at this level anymore. I made sure for as long as I could I would still fight for my dream, my passion. I was very lucky to have had such a great run, but now it’s time to fight another battle.”

No further medical details were released.

Simms, a defensive midfielder, is fifth on United’s career list in regular season appearances (182) and sixth in starts (147).

He made one U.S. national team appearance: against England in 2005 in Chicago.

Simms will remain in the Boston area, where he is opening an indoor cycling studio this year.

[Among the many stories I wrote about Simms during his DCU career, I enjoyed reporting this one the most.]