Tom Johnson was a pitcher from St. Paul. He offered the combination of being a terrific person and highly competitive. Those two factors would put a premature end to his major league career.

Johnson was called up by the Twins in July 1976 and became an important reliever in front of Bill Campbell. When Campbell left as a free agent after that season, manager Gene Mauch told Johnson over the winter, “Bill is gone; you’re my guy.’ ”

I was a Twins beat writer during Mauch’s time with the Twins and appreciated him greatly. Yet, there was a major flaw in the way he managed a team:

Mauch would give relievers he trusted an incredible workload.

Campbell pitched in 78 games, finished 68, worked 167⅔ innings and had a 17-5 record in 1976. The Twins were a hitting machine in 1977, and Mauch tried to put the same burden on Johnson: 71 games, 146⅔ innings and a 16-7 record.

There was tenderness in Johnson’s right shoulder over the final weeks of the season. Mauch said it was caused by his “delivery.” Johnson said it was from overwork.

Johnson spent a large hunk of the 1978 season on the disabled list. He made his 18th and last appearance of the season on Sept. 27.

He was taking injections of Butazolidin, a now-banned anti-inflammatory medication. Finally, in the offseason, Johnson went to see Dr. Frank Jobe and was told that he had a torn rotator cuff in his right shoulder.

The Twins’ response was to release him in February, before Johnson underwent surgery. Johnson never pitched again in the major leagues. He had sacrificed his career while pitching with shoulder pain that was mostly ignored by the Twins in 1977.

No relief pitcher would be used in modern times as Johnson was by Mauch and the Twins four decades ago. Yet, there’s a lesson here:

Pitchers are athletes like none other, in that they are required to make their arms work in an unusual way thousands of times per year.

As a vital part of the throwing mechanism, the elbow gets the most attention because of Tommy John surgery. It’s the shoulder that remains more complicated because of the moving parts.

Two of the pitchers identified among the culprits in the Twins’ Great Collapse of 2016 were closer Glen Perkins and starter Phil Hughes.

Perkins was lucky to reach 90 miles per hour with his fastball in spring training. He was 95-plus when needed during three consecutive All-Star seasons.

His fastball still was missing in two ineffective April appearances. He said that his left shoulder didn’t feel right and went on the disabled list.

There was leftover resentment toward Perkins for his miserable final weeks in 2015. And then with the Twins’ 0-9 start, the party line in public forums became:

“Whenever Perkins has a bad stretch, he complains about a physical problem.”

Go for it, folks, but what puzzled me was this: Why was Perkins throwing 89, rather than 6 miles per hour faster, if there wasn’t something wrong?

It turns out there was. The labrum in his left shoulder, which contributes to shoulder stability, was torn.

It was repaired by being tacked to the bone in surgery last week. Perkins might be able to pitch again in eight months. Or not.

There was another case of the missing fastball with Hughes. He was a No. 1 starter in 2014, throwing constant strikes in the mid-90s. The Twins tore up his contract for a lucrative five-year deal.

Hughes’ fastball wasn’t the same in 2015 and he had a bad season. The Twins saw a pitcher who was out of shape. They asked Hughes to lose weight in the offseason, and he did so dramatically.

The velocity still was missing. A fastball pitcher without his good fastball is in trouble.

The public vilification of Hughes reached its zenith on May 17 in Detroit. He took a 2-0 lead into the seventh, but had warned the Twins earlier that he felt as if his right shoulder was fatigued.

Two long fly balls — a triple and sacrifice fly — and Hughes departed after 75 pitches. Even Bert Blyleven, from the usually supportive Twins TV booth, aimed derision at Hughes.

It became a fact on Twitter and elsewhere: Phil Hughes was soft.

He was hooked from the rotation after a bad start vs. Tampa Bay on June 2. Seven days later, pitching in relief, Hughes was drilled with a line drive and suffered a fracture in his left knee.

It was announced Tuesday that Hughes had another problem that could explain shoulder fatigue and a still-missing fastball: Something called “thoracic outlet syndrome” that will cause him to have part of a rib removed under his right shoulder blade.

When Hughes raised his right arm above his head, he was losing feeling in his hand … not exactly optimum for a big-league pitcher.

The ability and willingness to fully diagnose shoulder problems with pitchers has increased mightily with modern sports medicine. Too bad Tom Johnson didn’t have that going for him in 1977. He was a great young man who deserved a much longer career.