On April 6, 1973, two letters changed Ron Blomberg’s life.

The lefty-swinging Yankee arrived at Fenway Park in Boston on opening day and found “DH” scribbled next to his name on the lineup card. He batted in the first inning and became the first designated hitter in Major League Baseball history.

A controversial change for some — and one the National League refused to adopt for decades — the position is now universal, having been permanently added to the N.L. upon the ratification of baseball’s new collective bargaining agreement.

Blomberg is all for it.

The position helped him stay off the disabled list in 1973, which was a bigger deal back then, and it inspired the Jewish ballplayer’s first book, “Designated Hebrew: The Ron Blomberg Story.”

Blomberg, 73, who lives in Atlanta, does not always enjoy the modern game. “It’s hard for me to watch,” he said, citing defensive shifts, the explosion of analytics and the lack of small ball and lengthy pitching performances as its flaws.

The expansion of the designated hitter, however, is a source of pride for him.

“Being the first D.H., I always tell people I screwed up the game of baseball,” he said with a laugh. “But now, instead of half a ballplayer, I became a whole ballplayer when it became the universal D.H. in both leagues.”

What does the world’s first designated hitter think of the universal designated hitter?

I think it’s great. They should have done this a long time ago.

To be honest with you, I never thought the D.H. was going to live this long. When I became the D.H. in ’73, I thought it was a short-term fix. Look at it now. It’s 49 years later. Unfortunately, the National League did not want to adopt it for whatever the reason was.

It puts a lot of interest in the game of baseball, and it puts a lot of offense in it. It’s a great position now. When I came up, basically it was like a part-time player. Now it’s a full-time player. In the last few years, you’ve got David Ortiz in the Hall of Fame, and of course Edgar Martinez became the first D.H. in the Hall of Fame. So it’s a position player now, and it’s going to stay. It’s a fixed part of the game.

What made you think it was going to be a short-term thing when it first came about?

I thought it was a joke. Nobody had any idea what it was. Everybody used to call it a pinch-hitter. Everybody thought it was a joke. This is what people used to do when they played stickball and out in the front yard. If you can’t hit, somebody’s going to hit for you.

When we went down to spring training in ’73, nobody had any idea what the D.H. was. Then we started to use it and all the teams started to use it. The pitchers, let’s be honest, 98 percent of the pitchers can’t hit. They don’t get paid to hit. But there are some great hitters that are pitchers.

If you look at it now, it’s a wasted at-bat in the National League, other than a few pitchers that can really hit.

It seems that very few pitchers are opposed to the designated hitter today. Was that the case when you were playing, or were pitchers mad about the rule when it was new?

They were totally mad because they wanted to hit. They always had contests. Pitchers on every big league team, basically what they did was whoever had the most hits would win a contest.

I know on my teams, Mel Stottlemyre was an excellent hitter. Fritz Peterson was an excellent hitter. They went out early and took B.P. They took it seriously. You’ve got a D.H. in Little League now. You’ve got a D.H. in high school. You’ve got a D.H. in college and the majority of the minor league system. Pitchers nowadays hardly take any B.P.

I know three or four high school pitchers whose parents won’t even let them pick up a bat. They don’t want them to get hurt.

Walk me through April 6, 1973, the day you became the first designated hitter. What was your reaction to seeing those two letters next to your name? Did you know you were going to D.H.?

Ralph Houk and Dick Howser and Elston Howard told me I was going to be the D.H. against Boston’s Luis Tiant. Down in spring training that year, I was not the D.H. at all. The reason I became the D.H. was because I injured myself five days before we broke camp in Fort Lauderdale. I pulled a hamstring. Dick Howser and Ralph Houk asked me if I could play. If you tell them you cannot play, if you go on the disabled list — and we had one-year contracts — and somebody had a good season down in Triple-A, it’s going to be like a Wally Pipp, like a Lou Gehrig.

There were also managers, even American League ones, who disliked the designated hitter rule. One persisting thought in the National League all these years is that a D.H. takes strategy out of the game. What do you say to that?

It absolutely doesn’t. What takes strategy out of the game is putting a pitcher in that can’t hit!

Other than increased offense, in what ways do you expect the universal designated hitter to impact the sport?

It’s going to save a lot of older players time in baseball. When I was the first D.H., I was a young guy, but the other guy I played against that game was Orlando Cepeda. Orlando had a few years on me, and it prolonged his career.

Nelson Cruz is an example. He’s 41 and just signed with Washington, a National League team. He would have never been able to do that in years past because he’s only a designated hitter. Are there any other players you think might benefit from the universal D.H., or guys who could have benefited in the past?

Nelson Cruz was a perfect guy for the D.H. Edgar Martinez was not the greatest third baseman, and he became a great D.H. You would have saved a lot of players more time, like Barry Bonds or Mark McGwire.

Those guys are known for historic home runs. Now you’ve got Albert Pujols, age 42, closing in on 700 homers. Maybe he gets that chance now that there are more D.H. jobs.

I totally agree because he was a heckuva good ballplayer, and he’s a heckuva good hitter. And he’s fun to watch even though he’s up in age. And people come out to watch him.

Putting up a pitcher that’s going to have a batting average of .031 and doesn’t know how to bunt? That’s not helping the game of baseball.

This interview has been edited for clarity and length.