The Houston Astros announced Wednesday that five players were moved to the injured list, but did not specify a reason for any of the designations.

Jose Altuve, Alex Bregman, Yordan Alvarez, Robel Garcia and Martin Maldonado were moved to the injured list.

General manager James Click later said the players were moved to the list because of the league's health and safety protocols, according to USA Today's Bob Nightengale. Click also told reporters that he did not think the team would need to postpone Wednesday's game. 

As a result, five players have been promoted to the active roster from the team's alternate training site. Taylor Jones, Garrett Stubbs, Abraham Toro, Alex De Goti and Ronnie Dawson are expected to join the team for Wednesday night's game against the Detroit Tigers. 

The Astros dealt with COVID-19-related issues in March, when eight pitchers were sent home from spring training because of health and safety protocols. The team did not pause activities at the time. 

Later in March, centerfielder Myles Straw was sidelined for issues related to COVID-19, but he returned in time to join the team for the opener. 

Houston is set to play the final game of a three-game series with Detroit, then scheduled to hit the road for a five-game road trip to Seattle and Colorado beginning Friday. 

Losing four starters in Alvarez, Altuve and Bregman—who are all in the top five on the team in batting average—and Maldonado is a significant blow for Houston especially heading into its upcoming series. The team is tied with Seattle in the AL West standings, with both teams at 6-5 and one game behind the 7-4 Los Angeles Angels for first place.