Minnesota United striker Mason Toye (shown in a 2019 match vs. Sporting Kansas City) said the Loons are preparing to beat the Orlando heat in the "MLS is Back" tournament. "We’ve been working hard to get acclimated to the weather, to the training times and the game times,” he said (Brian Wicker — Star Tribune/The Minnesota Star Tribune)

Major League Soccer on Wednesday is set to become the first U.S. major pro sports league to return after four months' shuttered by the coronavirus pandemic. Its 54-game, monthlong "MLS is Back" tournament in Orlando will feature another opponent beyond the other team's 11:

Florida's summer heat.

The league has modified its substitution rules to allow each team five instead of three and has expanded its game-day rosters by five players to 23. It also adjusted starting times so games with be played only at 9 a.m. and 8 and 10:30 p.m. Eastern time at ESPN Wide World of Sports Complex at Walt Disney World.

Minnesota United players under coach Adrian Heath's direction have trained evenings or mornings since they arrived. They scrimmaged against each other Sunday evening after a scheduled one against Columbus Crew SC was canceled on short notice because of what a Loons spokesperson called "an overabundance of caution" after a Crew player tested positive.

On Monday, FC Dallas withdrew from the tournament after 10 of its players tested positive. Two Nashville players also tested positive out of 557 players who were in Orlando.

The Loons play their first of three Group D games Sunday against Sporting Kansas City in that 8 p.m. Eastern time slot. Their other two group games will be in that late slot, 10:30 p.m. Eastern time. MLS' two Florida teams — Orlando City and Inter Miami — kick off the tournament Wednesday.

"It has been difficult with the humidity, but we know that," Minnesota United striker Mason Toye said. "And Adrian tells us before every session that every team is going through the same thing. So we just have to get on with it. We've been working hard to get acclimated to the weather, to the training times and the game times."

MLS is restarting its season in Orlando after Florida Gov. Ron DeSantis extended invitations to pro sports when many other states hadn't yet declared themselves open for business and before COVID-19 cases recently spiked in the state. Both MLS and the NBA accepted, making extensive plans to play without fans, sequestered in facilities near Walt Disney World.

It also did so despite the weather.

MLS all-time goal scorer Chris Wondolowski, whose San Jose team was the first to arrive, advises "bring water and stay hydrated. It's hot down here." Loons midfielder Robin Lod was born and raised in Finland, but has played during summers in Greece and Spain.

"I'm used to it," Lod said. "Circumstances aren't the most ideal, but they're the same for everyone."

Most participating players haven't played at 9 a.m. or 10:30 p.m. since their youth soccer days. Loons midfielder Jacori Hayes and defender Chase Gasper played such games. They also played on the same 17 fields that MLS is using for team training and games when each played in the Disney Soccer Showcase when they were kids.

"It's funny being on this training field," Hayes said. "It's fond memories of childhood, playing on these fields."

New England striker Adam Buksa played there, too, with his Krakow, Poland, team that won its division when he was 12.

"I know what to expect from the weather," Buksa said. "The conditions will be the same for every team. It's not going to be easier or hard for any of the teams. It might influence a little bit the tempo of the game, but everything will be fine. You just have to play smart."

The Loons escaped that 9 a.m. slot. They play their first group game at 8 p.m. Orlando time, their final two at 10:30 p.m. They scheduled Sunday's scrimmage with Columbus specifically for the night.

Columbus arrived a week earlier than it would have so it could scrimmage the Loons in preparation for three group-round games that will count in the 2020 MLS standings. That scrimmage was canceled out of precaution after that positive test. The team has trained in the evening to prepare for two games at 10:30 p.m. and one at 8 p.m..

"We feel it's really important to get into an evening rhythm," Columbus coach Caleb Porter said on MLS' "Extra Time" podcast. "It's an important decision for our preparation because 10:30 is not a game time we've ever played in. We need our players to get used to it."

Heath remembers a midnight game he played long ago with a team in Spain.

"First time I had a start nearly in the next day," Heath said. "The nighttime games under the lights will add a little more atmosphere. It's going to be a late start. That will be a new one for most of our players as well."