Twenty years ago, interleague play began. There have been many changes since then -- instant replay, two wild-card teams per league, divisional realignment, the All-Star Game determining home-field advantage in the World Series, the steroid era, four fingers for an intentional walk and alterations to sliding rules to protect catchers and middle infielders. The changes have come swiftly, and soon will come even more swiftly, which makes us wonder: What will the game look like in 20 years?

Thankfully, it will look, feel and sound much like the game that has been played for the past 125 years, with nine innings, three outs, four balls and three strikes, 60 feet, 6 inches between the mound and home plate and 90 feet around each side of the diamond. Baseball is too good, too rich in history and tradition to make modifications that would deeply affect the fabric of a game that's so special for so many. But it will be different, and to speculate just how different, we asked 12 people in baseball, including managers, general managers, players and umpires, and this is their collaborative projection/guess on what the game will look like, not should look like, in 2037. The massive changes ahead are rooted in three principles: speed up the game, make the game safer and keep it wildly profitable.

Pace of play is currently No. 1 on commissioner Rob Manfred's list of improvements, and it will remain a huge topic over the next 20 years. In 2037, there will be a pitch clock -- 20 seconds between pitches, if a pitcher goes past that, a ball will be assessed -- so we won't have to endure anything like Pedro Baez's torturous relief appearances, Josh Beckett taking 53 seconds between pitches or first baseman Mark Grace screaming at pitcher Steve Trachsel, "Throw the f---ing ball, it's hot out here!'' -- and they were teammates.

There is little doubt that a pitch clock will be added to the game within the next 20 years. Mark J. Rebilas/USA TODAY Sports

There will be a limit on trips to the mound during a game by a pitching coach, catcher or infielder -- call them timeouts: five per game, more will result in the ejection of the player or coach. Hitters will not be allowed to step out of the box after a pitch, the penalty being a strike added to the count. And the tradition of throwing the ball around the horn after an out will be eliminated. The catcher will just throw the ball to the pitcher.

There will be no ties in baseball, but the 12th inning will begin with a runner on second base. If the score is still tied after 12 innings, the 13th inning will begin with a runner on third base. This surely will end the wonderful craziness of teams playing 20 innings, but the days of a five-hour game that finishes at 2:45 a.m., essentially will be over, bullpens will be saved from overwork, deadlines will be met and everyone involved will get more sleep. And to help prevent rain delays, every ballpark built starting in 2030 will be required to have a retractable roof. Meanwhile, in-ground tarpaulin technology will be developed by 2037 to cover a field more efficiently and eliminate having a tarp in play.

Expect to see sabermetric coaches in every dugout assisting the manager in the future. Kim Klement/USA TODAY Sports

The role of the manager will not be eliminated, as some in the sabermetric community have suggested, because there will be a great deal of in-game strategy, especially with the new rule on extra innings. But there will be a sabermetric coach in uniform on the bench with a laptop or some sort of device to help assist the manager. This is happening all the time now, a team of stat guys providing data to the manager, just not in the dugout during the game. In 20 years, we'll be measuring variables that'll make exit velocity and spin rate look like fifth-grade math, but the human element will make a comeback as the game recognizes that Bruce Bochy is a better judge of talent than a scientist who says Tony Gwynn wasn't great, he was lucky, because his exit velocity wasn't particularly high.

The sabermetric revolution has birthed an era of radical shifting -- three players on one side of the infield, a second baseman playing shallow right field. Shifting will remain legal, and we will not have four-man outfields because the irritating all-or-nothing approach in the game -- a home run or a strikeout, and not much in between -- will eventually self-correct as hitters finally adjust and learn to use the whole field.

It will all be about safety moving forward. And it will start with the fans. Protective netting in 2037 will run from foul pole to foul pole, as it does at the Little League World Series in Williamsport, Pennsylvania, providing great relief that no fan, including the one with his face buried in his cell phone, will get hit in the head by a baseball traveling at more than 100 mph.

Pitchers will be forced to wear protective helmets as players continue to get bigger and stronger. Brad Penner/USA TODAY Sports

It is a miracle that no pitcher has ever been killed by a line drive, but with the size and strength of today's hitters, a fatality seems inevitable, and it's frightening to think that 20 years from now, 20 players will be as big as Giancarlo Stanton and Aaron Judge. So, pitchers will be required to wear helmets or specially designed caps with protective liners in them. In an attempt to better protect hitters, perhaps as early as next season, all baseballs will have a tackier feel, allowing the pitcher a better grip. Also in the next year, a pine tar rag will be placed on the mound to help ensure that a batter doesn't get injured because the ball slipped out of the pitcher's hand. If a pitcher does use an illegal substance, that violation can be enforced correctly by the umpires.

In 20 years, all players will be monitored to an intense degree. Heart rate and brain function will be watched in several ways, including through the bloodstream, and will detect when the stress level, among other levels, is too high. The monitors will determine when a player reaches failure capacity, which could reduce the risk of injury and alert a performance risk. It's a paradox: Players are bigger, stronger and fitter today, but they get hurt more often. There will be far more healthy players and less use for the disabled list in 2037.

There will be a greater effort to outlaw takeout slides at second base, further eliminating the artistry of our best middle infielders, and rewarding those middle infielders with poor footwork and poor decision-making around the bag. Penalties will increase -- a 20-game suspension, at least -- for pitchers that gratuitously hit a batter with a 98 mph fastball because that pitcher -- the latest being the Giants' Hunter Strickland hitting Bryce Harper -- simply wasn't good enough to get him out. But baseball is filled with remorseless, vengeful players; retaliation is never going away; it will always be a hard game played by hard men. Human emotion is a difficult variable to control or eliminate.

Umpires, like Joe West, will still be around for managers, like Joe Maddon, to fight with in 20 years. Jeff Curry/USA TODAY Sports

Most of these changes will require even greater involvement from our umpires. There will still be four umpires on the field as opposed to sensors on player's uniforms and on each base to electronically determine out or safe calls. Instead of having a laser system at home plate to call balls and strikes because such a system can't always account for the shifting size of a player's strike zone or the element of a crouch, the home plate umpire will be standing behind the pitcher's mound. Many in the game will acknowledge that is the best vantage point to call balls and strikes, especially the horizontal strike zone -- inside and outside. For the vertical ball/strike call (high or low) advanced technology will provide an augmented reality for umpires, it will help them better see what they see. The home plate umpire will touch a receiver on his belt and receive a signal, such as a buzz, to help him better call a pitch.

The rosters will be expanded from 25 to 27, with a taxi squad to protect pitchers from overwork. Two-way players will be common; every team will have a couple who will DH on days that they don't pitch, improving roster flexibility. The DH will be universal, ending what will be a half century of absurdity of having different rules in each league.

But as much as the game will try to become safer, the players will still be asked to play 162 games a year, not 154, not 140. That's because MLB always protects its statistics, but mostly it's because owners won't be willing to forfeit roughly $2 million to $3 million per home date. There will be no American League and National League, it will all be under one MLB. There will be no Oakland Athletics or Tampa Bay Rays. The game will not expand to Mexico or Japan or Las Vegas. Instead, it will contract from 30 to 28 teams. That will make scheduling easier and more equitable: All teams will play each other six times, 27 times six equals 162. The top 10 teams in the game will make the playoffs.

Like any $10 billion industry, it will all be about revenue. That's why, long before 2037, all that space on a player's uniform will be used for free marketing and advertising purposes, à la NASCAR. Indeed, put AT&T on Kris Bryant's helmet and see how many phones you sell the next day. We're already there with special uniforms used on holidays, etc.; it will only be expanded to the point that players will become walking billboards. And all teams will have lucrative naming rights for ballparks, including Fenway and Wrigley.

Soon there won't be any blank space on jerseys, as the opportunity to bring in more ad revenue will be too great to stop. Patrick McDermott/USA TODAY Sports

As revenues continue to skyrocket, so will player salaries. Harper might become the first $400 million player, unless it's $500 million, after the 2018 season. Then Mike Trout will bury that once he becomes a free agent after the 2020 season. By 2037, a dozen players will be awarded contracts in excess of half a billion dollars. But ticket prices also will rise to a level that will make it even less affordable than today to attend a game.

With all that money to be made, players will find a way to get the most they can, even if it means using performance enhancing drugs. As long as the carrot is there, as long as there is motivation and there are wildly competitive players, there will be those players that will try to beat the system, as there is, for example, with insider trading. There will always be new designer steroids, and there will always be more chemists trying to make them undetectable.

There are sobering thoughts about the future. The amateur draft doesn't work and needs a total overhaul. Escalating salaries and the thorny issue of dividing owner revenues will force the first work stoppage -- it will be nasty -- in the game since the 1990s.

Change is inevitable and change is often good, but with change comes concern. We worry that the game is changing too much, too quickly. Baseball has always provided a way for us to relax. Baseball provides a space to spend more time with friends and family at a game. Yet as we move forward, we want fewer games, fewer teams, fewer innings, fewer pitches, fewer pitchers, fewer three-hour games and less human involvement. That could mean fewer human beings attending games and fewer being interested in baseball.

The game always will be great. But as we move toward 2037, let's hope less is indeed more.