Southern Methodist special teams coordinator Frank Gansz Sr., a legend in the NFL for his ability to coach the kicking game, is in grave condition in a Dallas hospital.
Mustangs head coach June Jones described Gansz's illness as "a serious situation," while meeting with reporters after practice Thursday.
Gansz, 70, underwent knee replacement surgery Wednesday at Presbyterian Hospital. He came out of surgery without any issues but suffered complications from a blood clot soon afterward, according to UCLA coach Rick Neuheisel.
Gansz's son, Frank Jr., who coaches special teams for the Bruins, went to Dallas.
During his 38 years of coaching, Gansz spent 24 years in the NFL with eight different teams (1978-2001). He served two seasons as head coach of the Kansas City Chiefs (1987-88), where he had a 8-22-1 record.
Gansz was hired in Detroit the following season and was named NFL Special Teams Coach of the Year. Gansz also coached special teams for the St. Louis Rams when they won the Super Bowl in the 1999 season. He retired from the Jacksonville Jaguars in 2001, only to be lured back to the field by Jones at SMU last year.
Gansz is a 1960 graduate of the U.S. Naval Academy, where he played center and linebacker.
According to findings published in February by the American Academy of Orthopedic Surgeons, two to three percent of the 700,000 patients who undergo hip or knee replacements in the United States each year suffer symptoms related to blood clots.
Ivan Maisel is a senior writer for ESPN.com.