Watch Now: MLB Latest: Coronavirus Test Delays Plaguing Baseball (3:16)

Major League Baseball resumed baseball activities earlier this month with spring training 2.0, also known as "summer camp." The hope is that MLB will be able to fit in a 60-game regular season (imposed by commissioner Rob Manfred) amid the coronavirus pandemicOpening Day is scheduled for next week. Two regular season games are on the calendar for July 23 and the rest of the league will begin play on July 24.

However, delays on COVID-19 test results throughout the league are making things more difficult for some squads. The concerns first arose last week when the Nationals and Astros (along with other teams) were forced to cancel workouts because of testing delays.

"Without accurate and timely testing, it is simply not safe for us to continue with summer camp," Nationals general manager Mike Rizzo said. "Major League Baseball needs to work quickly to resolve issues with their process and their lab. Otherwise, summer camp and the 2020 season are at risk."

The league responded to the testing delays in a statement last week and attributed delays to the July 4 holiday weekend. MLB said it did not expect delays to continue.

But on Monday, the Chicago Cubs also said they were experiencing a similar problem. Cubs manager David Ross and five other tier-1 individuals were still awaiting their test results from Saturday, and therefore, were not going to attend Monday morning's workout.

"We've decided to do the prudent thing so myself and the five others will not attend this morning's workout," Ross said in a statement. "Out of an abundance of caution, we think it makes sense for the six of us to wait for clarity.  Situations like this have not been a worrisome indicator of a positive test result to date."

The Astros also continue to deal with testing delays. On Monday, the club was still awaiting COVID-19 test results for their pitchers, forcing a delay to the start of their workoutHouston also canceled its Sunday workout due to potential exposure to someone who had been infected with the novel coronavirus.

Veteran Braves outfielder Nick Markakis was one of the players to opt-out of the 2020,  and he was swayed by a conversation with teammate Freddie Freeman, who was diagnosed with COVID-19 and experienced mild symptoms. Giants catcher Buster Posey and Dodgers left David Price were among some of the other notable players who announced their decision to sit out this season.

In some COVID-19 cases, a person may be asymptomatic and not show any signs of symptoms. Royals catcher Salvador Perez tested positive, but was asymptomatic and required to spend a 14-day quarantine at home.

Although coronavirus is considered a respiratory illness, the disease can impact a number of systems and organs. That includes possible effects on the heart and the brain. More than 130,000 Americans have died this year from COVID-19.