J.R. Richard, a flame-throwing right-handed pitcher whose scintillating career with the Houston Astros was cut short by a stroke in 1980, died on Wednesday. He was 71.

The Astros announced his death but did not give a cause or say where he died.

Richard was one of the most intimidating pitchers in baseball in the late 1970s. He stood 6-foot-8, his fastball approached 100 miles per hour, and his long stride toward home plate made him appear uncomfortably close to batters. He also had a devastating slider.

“When he pushes off that mound,” the Pittsburgh Pirate slugger Dave Parker told Sports Illustrated in 1978, “he looks like he’s 10 feet away from you instead of 60. It causes you to lean a little bit and makes you think you have to swing the bat quicker.”

After a few years in the minor leagues, Richard became a full-time member of the Astros’ starting rotation in 1975. Over the next four seasons he won 74 games and led baseball twice in strikeouts (with 303 in 1978 and 313 in 1979) and once in earned run average (with 2.71 in 1979). He could be wild; in 1976, he walked 151 batters.

He was pitching well in 1980 but had not completed as many games as he thought he should have when, in mid-June, he began to feel fatigue in his throwing arm — although that did not prevent him from starting the All-Star Game on July 8. (He struck out three in two innings.)

During his next start, though, he seemed lethargic, felt nauseated and had trouble seeing his catcher’s signals. After three and a third innings, he left the game.

At the time, he had a 10-4 record with a 1.90 e.r.a.

After Richard was placed on the disabled list, testing discovered a clot that was blocking the primary circulation to his pitching arm. His doctors chose not to operate, fearing that it might hurt his ability to pitch, but they let him work out. On July 30, while playing catch at the Astrodome, he felt a series of cascading symptoms that added up to a stroke.

In “Still Throwing Heat: Strikeouts, the Streets, and a Second Chance” (2015, with Lew Freedman), he recalled: “All of a sudden, I felt a high-pitched tone ringing in my left ear. And then I threw couple of more pitches and became nauseated. A few minutes later, I threw a couple more pitches, then the feeling got so bad, I was losing my equilibrium. I went down on the AstroTurf. I had a headache, some confusion in my mind, and I felt weakness in my body.”

He was taken to a hospital, where he was found to have no pulse in his carotid artery. Surgeons performed emergency surgery to remove a clot from the junction of two arteries in Richard’s neck.

The discovery that Richard had a life-threatening condition was proof that he was not lazy, as some members of the press and fans had been saying, and that his complaints of arm fatigue should have been taken more seriously.

“Deep down in my heart, I knew something was wrong,” Richard said in his autobiography. “At that moment I was just about the best pitcher in baseball. Why wouldn’t I want to pitch?”

James Rodney Richard was born on March 7, 1950, in Vienna, La. His father, James Clayton Richard, was a lumber grader. His mother, Elizabeth (Frost) Richard, was an elementary-school cook.

In high school, Richard played baseball and football and turned down numerous college scholarships to play basketball. He was chosen by the Astros second overall in Major League Baseball’s amateur draft. He played in Houston’s minor league system, and in his first call-up to the Astros, in 1971, he had an auspicious debut against the San Francisco Giants: He had 15 strikeouts, including three of Willie Mays.

He joined the Astros for good in July 1974.

“Nobody wanted to face him,” his teammate Enos Cabell said in a statement released on Thursday by the Astros. “Guys on the other team would say that they were sick to avoid facing him.”

In 1980, the Astros added Nolan Ryan to their rotation, posted a record of 93-70 and advanced to the National League Championship Series, where they lost to the Philadelphia Phillies. (The Astros moved to the American League in 2013.)

The Astros advanced without Richard, who never pitched for them again. He tried a comeback but after 21 games in the Astros’ minor league system, he was released in 1983.

He had some difficult times afterward. He lost money in business ventures and was divorced twice. During parts of 1994 and 1995, he was homeless, living under a bridge in Houston. A big man, he was not hard for people to recognize.

“First of all they can’t believe it, and then no one would really want to bother you,” he told Bill Littlefield of the Boston public radio station WBUR in 2015. “They’d probably look at you and say, ‘OK, he don’t look like he’s a happy camper.’ I looked like I wasn’t a man to be messed with at that time.”

He got help from a local pastor and the Baseball Assistance Team, which helps indigent former players. He found a job in construction and eventually became a minister at a church, where he helped the homeless and taught baseball to children. (Complete information on survivors was not immediately available.)

Richard said that his stroke had affected his reflexes on the left side and sometimes his speech. But he never forgot what it was like to dominate hitters.

“It was grand, to be in control,” he told The New York Times in 2015. “You didn’t fear no one. You had respect for them as a human being; they could hit a home run as well as you could strike them out. But I felt like I was the baddest lion in the valley.”

Alex Traub contributed reporting.