McDaniel, 59, fell ill after traveling to Washington, D.C., to visit a family member, according to LSU track and field coach Dennis Shaver.
McDaniel, from Shreveport, Louisiana, was an all-state performer at Lake Charles High School. At LSU, he caught 64 passes for 1,184 yards with three touchdowns in four seasons from 1978 through 1981. In 1981, he averaged 17.5 yards per catch, which ranked second in the SEC.
In track, McDaniel won an SEC championship in the 110-meter hurdles and finished second in that event at the 1980 NCAA Division I Outdoor Track and Field Championships. He was named All-American in the 60-yard hurdles in 1980 and 110 hurdles in 1980 and '81.
McDaniel still ranks tied for third in LSU history in the 55 indoor hurdles and tied for ninth in the 110 outdoor hurdles.
McDaniel was a second-round pick of the Broncos in 1982 and played three games without a catch as a rookie.
According to McDaniel's LinkedIn profile, he founded the North Texas Cheetahs Youth Track Club in 2003.
Shaver said McDaniel was among the most prominent youth track coaches in the country and mentored hundreds of athletes and other coaches.
"He was such a tremendous athlete in both sports, but the love he had for track and field was really special," Shaver said. "We're fortunate that people like him get involved with our youth.
"He was one of the most important people in our sport. He had to persuade youth to spend their summers doing something productive. Orlando had essentially dedicated his life to it. They'd come to summer meets and have two busloads full of people. It was a real impressive group of people. He's sorely going to be missed."