CLEVELAND—Mike Trout, the Los Angeles Angels’ centre fielder and perhaps baseball’s best player, drew a walk here this past week, trotted to first base and put on a protective sliding glove that resembled an oven mitt.

Trout, a two-time most valuable player in the American League, is one of three prominent players who have hurt their thumbs and fingers while sliding headfirst this season, along with Carlos Correa, the Houston Astros’ all-star shortstop, and Kris Bryant, the Chicago Cubs’ third baseman and the reigning MVP in the National League.

These high-profile incidents have occurred soon after the publication of the first in-depth study about the frequency and effects of sliding injuries in professional baseball. The study suggests it could be more risky to slide headfirst, which some players prefer for strategic reasons.

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“It’s a growing topic, for sure,” said Jeff Luhnow, the general manager of the Astros.

The study, published in May in The American Journal of Sports Medicine, tracked all sliding injuries to baserunners in the major leagues and minor leagues from 2011 to 2015 that resulted in at least one missed day of play.

The study, partly funded by Major League Baseball and employing its injury database, found 236 sliding injuries overall during those five seasons, which is not necessarily a large number.

“I was surprised with how few injuries actually occurred while sliding,” said Dr. Christopher L. Camp, the lead author of the study and an assistant professor of orthopedics at the Mayo Clinic in Rochester, Minnesota.

Yet during the period of the study, marquee players such as Bryce Harper and Ryan Zimmerman of the Washington Nationals; Josh Hamilton, then of the Angels; Yasiel Puig of the Los Angeles Dodgers; and Dustin Pedroia of the Boston Red Sox all suffered hand injuries while sliding or diving into a base headfirst.

When such injuries do occur, the study showed, time missed from play can be considerable. On average, major-leaguers missed 15.3 days for a sliding injury. And more than 12 per cent of those injuries required surgery, when the average absence grew to two months for major leaguers and minor leaguers as a group.

The study seemed to affirm the long-held belief among players and managers that it can be more dangerous to slide headfirst, even as many consider it a more effective tactic than sliding feet first if the purpose is to avoid tags.

Video analysis of half of the games played in the major leagues in 2015, pro-rated for the entire season, estimated the rate of injury to be one for every 249 headfirst slides, compared with one for every 413 feet-first slides.

A larger sample size would be needed for the variance to be statistically significant, Camp said in a telephone interview, but he added, “I think if we had higher numbers, that would bear out as a statistically significant difference, most certainly.”

Trout tore a ligament in his left thumb on May 28 while stealing second base, underwent surgery and missed more than six weeks before returning after the all-star break.

His case was typical of what the study found for major leaguers and minor leaguers: Sliding injuries are nearly four times more likely to occur at second base than at other bases. And hands, fingers and thumbs, with their fine architecture, were approximately twice as likely to be injured as ankles and knees.

“He’s kind of the prototypical example, unfortunately,” Camp said of Trout.

In the absence of their star for 39 games, the Angels muddled along below .500 and fell an additional 5 ½ games behind the Astros in the AL West.

“The effect of these injuries based on time out of play and lost productivity is vast,” the study said.

Correa, the Houston shortstop, jammed his left thumb while sliding into a catcher’s shin guard at home plate in early July. Pain persisted through the all-star break, and then Correa left a game on July 17 after an aching swing-and-miss during an at-bat. He was found to have a torn ligament in his left thumb and is expected to be out until September.

Bryant, of the Cubs, sprained the little finger on his left hand on July 19, striking a third baseman’s foot as he slid awkwardly while trying to advance on a wild pitch. He missed only one game, but he said this past week that a nagging soreness remained in the finger.

Managers generally discourage players from sliding headfirst at first base and home plate, but there are exceptions depending on the particular play. The widespread feeling is that major leaguers should make their own decisions in the moment and that injuries are an inevitable part of the game.

“A lot of what we do on the field is instinctual, not instructional,” said A.J. Hinch, the Astros’ manager.

At the minor-league level, where there are many more teams and a correspondingly higher number of sliding injuries, the Angels require players who tend to slide headfirst to wear thumb guards, manager Mike Scioscia said. In the past, the Astros removed minor leaguers from games if they slid headfirst into first or home.

Players in Pittsburgh’s farm system who have injured their hands, fingers or shoulders can be fined for sliding headfirst. So can players who tend to rely more on brawn than speed.

But, said Larry Broadway, the Pirates’ director of minor-league operations: “Typically, you don’t really get to that point. Guys know that if they’re not supposed to, they don’t do it.”

Major leaguers who prefer to slide headfirst say it is easier to avoid tags and to remain on the bag with their hands rather than with their feet. Many also say it feels faster to slide headfirst.

The theory is that outstretched hands extend farther than feet ahead of the body’s centre of gravity, located in the pelvic area and the reference point for velocity. Thus, headfirst slides should reach the bag slightly quicker. The difference might be two-hundredths of a second, the equivalent of a few inches, which can make the difference between being safe or out. But sliding involves many variables, and the available science is contradictory.

“It’s not completely obvious you will always get there quicker one way or the other,” said Alan M. Nathan, a retired physicist at the University of Illinois who studies the physics of baseball. “My take from the experiments is that it’s so close, on average, it’s a wash.”

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In any case, both Trout and Bryant said in interviews they would continue to slide headfirst.

“It was a freak thing,” Trout said of his injury. “After your first slide, you tend to forget about it. I’m not going to switch.”

Bryant said before a game against the White Sox: “There are ways to manoeuvre your hands so they can’t tag you. But with me sliding feet first, my feet are big, my legs are big — it’s so much easier to tag someone out.”

But Alex Bregman, Houston’s third baseman, said he was reconsidering the headfirst slide in the wake of extended absences by Correa and Trout.

“I’ve always been a headfirst guy,” Bregman said before a recent game in Philadelphia. “But to be honest with you, you’ve got to consider sliding feet first after you see all these guys going” on the disabled list.

“I’m thinking about it, or getting a mitt to put on my hand when I slide,” Bregman said. “I think that’s the go-to move. It’s not worth the two months, you know?”

Camp, a one-time first baseman at Lee University in Tennessee, said the evidence was not yet compelling enough to call for a ban, or restriction, on headfirst sliding.

“I think we need to see a much more dramatic difference in injury rates and injury severities before we start advocating for any rule change,” he said.

Instead, the study recommended the use of hand guards and taping as a preventive measure. And it suggested the possibility of using bases softer than the current bags, or breakaway bases instead of those anchored by small posts. But further research on the bases is needed before changes could be enacted in professional baseball, Camp said.

Joe Maddon, the Cubs’ manager, said softer bases or breakaway bases could disrupt players who pivot on a base while running or turning a double play, and might even cause more injuries.

“Be careful what you wish for,” he said.

But Bryant said he would welcome softer bases. And Ben Zobrist, the Cubs’ versatile infielder and outfielder who dislocated a thumb on a headfirst slide in 2014, said he would prefer bases that were tethered with straps instead of anchored with posts.

“I’d be all for going back to something like that, something you slide into and it stays there, but it’s got softness to it and is going to move a little bit,” Zobrist said. That, he added, seems “so much safer.”

Asked its position on headfirst slides, Major League Baseball noted that its rules did not distinguish between headfirst and feet-first slides. And it pointed to two recent changes to enhance safety: Catchers cannot block the plate without possessing the ball, and on potential double plays, runners cannot change their path to the base or use a roll block to make contact with fielders.

The players’ association said in an email that it “constantly monitors the health and safety of our players; and that takes into account concerns in every aspect of the players’ workplace.”

Ron Roenicke, the Angels’ third-base coach, said that instant replay might be discouraging some players from sliding feet first in fear that they will be called out on review for coming off the bag ever so slightly while completing their slides.

Roenicke said instant replay should not be used for such purposes. The system, he said, should not allow for infielders “to sit there and tag a guy and follow him the whole way as he’s standing up.”

Scioscia, the Angels’ manager, disagreed, saying the letter of the rule should be followed.

However, Scioscia predicted, players will adjust, both to avoid injuries and to avoid being called out for briefly coming off the base. Improved techniques are emerging for headfirst slides — landing on the chest, shoulders spread, hands up. And already, Scioscia said, players seem to be beginning their slides somewhat earlier because of instant replay, making a conscious effort to stay under control, keep their hands or feet on the base and remain safe.

“The game will adapt,” he said.