The Tampa Bay Rays are not supposed to be in first place in the AL East. Since 2008, the Rays have never ranked higher than 20th in payroll. This season, the Rays opened with a payroll $176 million less than the Red Sox and $144 million less than the Yankees. There are underdogs and then there are the Rays.

Yet, it’s a few weeks into the 2019 season, and the Rays are still in first place. And our projections predict that they’ll be a playoff team. It’s still early, of course, and the Rays’ hot start could cool as more games are played — and they did take a tumble over the weekend against the Red Sox. But they’ve been so successful — going into the weekend, their pitching staff had the lowest ERA and fielding-independent pitching in the majors and no lineup was making more quality contact, for example — that it’s worth trying to make sense of how the Rays are defying the odds. It’s not just homegrown talent and innovative strategies propelling them this year, though the defensive shifts and the reliever openers are still happening. Instead, they’ve found yet another way to win: They’re getting more out of other clubs’ players.

Their top two and three of their top six position players this season were acquired from teams via trade during the last calendar year, and the 2.5 wins above replacement (WAR), according to FanGraphs’ measurement, of those three accounts for almost half of the Rays’ position player total. And their top pitcher to date, Tyler Glasnow, was acquired in the same July 31 trade with the Pittsburgh Pirates that brought them their best position player, Austin Meadows.

“We feel very strongly about our ability to get the best out of guys,” Chaim Bloom, Tampa’s vice president of baseball operations, told FiveThirtyEight last summer.

Two of those guys — third baseman Yandy Diaz, acquired in a December trade, and Glasnow — provide a glimpse into what the Rays might be doing right, and why this surprising start might be sustainable.

Prior to arriving in Tampa, Diaz was known for an excellent batting eye and elite exit velocity. From 2017-18, among batters to put at least 200 balls in play, Diaz ranked 13th in average exit velocity (91.7 mph). But that didn’t translate to power as well as we might have expected. He hit only one home run in 299 plate appearances in Cleveland and had the fourth-lowest launch angle among that same cohort, at 1.9 degrees. (The MLB average this season is 12.3 degrees.) Diaz was pounding ground balls into the turf too often.

Another issue last season: Diaz hit 57.1 percent of balls in the air to the opposite field, the fourth-highest mark in the league. That’s not conducive to power: Leaguewide this season, 33.4 percent of fly balls hit to the pull side have gone for homers but just 5.2 percent of those hit to the opposite field.

It’s not an ideal batted-ball profile for a player who, well, has muscles like these:

Yandy Diaz is seriously jacked and ready to take the Cleveland Indians to another World Series. https://t.co/MK7FiTmvWb pic.twitter.com/mBYnuYYCwQ — Muscle & Fitness (@muscle_fitness) April 4, 2017

But the Rays had a plan to get more out of all their batters, particularly those with Diaz’s tendencies. During spring training this year in Port Charlotte, Florida, hitting coach Chad Mottola and the Rays came up with an idea for a practice constraint: They were going to build an on-field wall.

They didn’t have what they needed at the spring facility, so they sent a truck 90 miles up I-75 to Tropicana Field, their major league home, to commandeer the netting typically used to shield players and coaches during batting practice. The next morning during batting practice, Rays hitters found a barrier of netting on the infield. They were asked to hit over it — to lift and pull the ball.

These are the screens #Rays have set up during BP to get hitters thinking more about launch angle, and hitting the ball in the air pic.twitter.com/lZEiwxirym — Marc Topkin (@TBTimes_Rays) February 15, 2018

“I saw it on the internet,” Mottola said of the practice, similar to what the University of Iowa called The Great Wall of Groundball Prevention in 2016. “I said, ‘Why don’t we just do it?’ At the major league level, it wasn’t anything more than a conversion starter. For younger kids, it was a way to stimulate thoughts more than anything.”

This spring, the Rays’ Great Wall of Groundball Prevention evolved to focus not just on trying to get the ball in the air but also on getting the ball in the air to batters’ pull side. The team also used pitching machines to produce velocity and spin more like what batters would see in actual games.

The Rays wanted to move the point at which hitters contacted the ball to out in front of the plate, which would allow them to pull the ball better, Mottola said. After all, that’s where the most power is generated. When Mottola began his coaching career in the Toronto organization in the late 2000s, he watched as Jose Bautista was taught to change his focus and try to pull everything. He became a star.

Whether because of the wall or something else, Diaz has changed the way he’s hitting this season. After an offseason of focus on contact point with the Rays, he’s now pulling 41.4 percent of batted balls, up from 28.9 percent last season — the 26th greatest increase in the sport. He’s hit five home runs in 89 plate appearances so far.

Diaz never pulled a home run in Cleveland. He has done so three times in Tampa.

“He was never given the opportunity with Cleveland in a way he thought he deserved,” Mottola said. “Letting him know he’s going to be in the lineup no matter how he plays today, that makes you a better player immediately.”

This season, the Rays have the second-lowest share of balls hit to the opposite field. (They had the highest share last season.) The Rays rank second in the majors in average exit velocity (90.3 mph), up from 26th last season (87.0 mph). It’s still early, of course, but those are marked changes.

The wall — or something — appears to be working.

With the Pirates last season, Glasnow, a once highly touted prospect, found himself in a long-relief role. He had lost his command and his confidence. What the Rays acquired at the trade deadline was a struggling pitcher, but one with intriguing underlying skills: a sharp breaking ball and a fastball that ranked at the top of the “perceived velocity” leaderboard since his debut. Glasnow’s average fastball of 96.7 mph looks like it’s going 99.3 mph because he releases the ball, on average, 7.6 feet in front of the pitching rubber. (He ranks first in the majors in perceived velocity this season.)

The data-heavy Rays began with a simple message to Glasnow: Trust that your fastball will still work in the strike zone.

“I tried to express to him that he could be really aggressive in the strike zone,” Rays pitching coach Kyle Snyder said. “The guy is 6-foot-8. He throws the ball from 52 and a half feet [from home plate]. He’s an upper 90s guy. It’s an all-power, no-art approach. I just think the more he understood that the hitter in the box had to respect the fastball and cheat to it, the better the breaking ball was going to be.”

Glasnow’s share of pitches thrown within the strike zone has increased by 4.7 percentage points this season, the 24th greatest improvement in the majors, just behind teammate and reigning AL Cy Young winner Blake Snell. While it’s early, Glasnow has also had the sixth-greatest decline in walk rate in the sport (5.9 percentage points).

Glasnow said the team also wanted him to focus on keeping his fastball elevated and his curveball down, while throwing the latter more frequently.

While he and the Pirates had agreed in 2018 to change his approach to one similar to what the Rays are espousing, Glasnow said it was hard to alter how he had thrown since being drafted in 2011. “The [Pirates] were very down in the zone, downhill angle,” he told FiveThirtyEight last September.

The Rays reinforced how his elevated fastball and 12-to-6 breaking curve could play together by sharing the same path, or tunnel, before the curveball breaks downward. Making the pitches look similar as they approached the plate would create confusion for batters.

“Tunneling is important,” Glasnow said. “It’s definitely more of an emphasis here.”

Consider the pitches working in tandem against the White Sox on April when Glasnow struck out 11 over six scoreless innings. His elevated fastball:

And his whiff-generating curveball, which currently ranks fifth in vertical movement and 15th in swing-and-miss rate among pitchers who have thrown at least 50 curves, falling below the zone:

Glasnow is first in the AL in ERA (1.53) so far this year after posting a 5.79 ERA in his two-plus seasons in Pittsburgh.

Glasnow and Diaz have made what appear to be real skill gains since arriving in Tampa. Of course, the sample size remains small early his season, and they will have to prove that their starts are sustainable. But if the Rays are indeed spinning developmental gold, the team may have landed on a path to long-term success.

Check out our latest MLB predictions.