The Rangers don't believe this will hinder Beltre's ability to be ready for Opening Day.
Beltre, 31, said he'll take it easy for the next three or four days, but that he still can swing a bat and do some activities that don't bother the calf. An MRI exam showed no tear or bleeding, and the Grade I is considered the least severe strain.
"Nobody wants to be hurt," Beltre said. "The positive side would be that it's better to happen now than during the season. I have time to get healthy."
Beltre got a guaranteed $80 million, five-year contract last month that also includes a vesting option for a sixth year and $16 million more. That free-agent signing prompted the Rangers to make six-time All-Star Michael Young, who played third base the past two seasons, their primary designated hitter and utility infielder.
Young was away from camp for the second day on Friday tending to a personal family matter, but was expected back Saturday.
Manager Ron Washington said he isn't planning for Young to be the everyday third baseman during Beltre's absence.
"I'm still going to move [Young] around down here in the spring," Washington said. "We have to get him versatile because we expect Beltre to be ready Opening Day. So Michael is going to play third, he's going to play at second, he's going to play at first, going to DH."
Beltre said he initially felt discomfort in his calf after working out on a treadmill at home about a week before reporting to spring training.
"I didn't feel a tweak, didn't feel anything unusual," Beltre said. "It started feeling sore after I was running."
The Rangers held him out of running drills and an intrasquad game this week. Beltre had the MRI Thursday after feeling more pain while taking ground balls.
"When it first happened, it was nothing serious. I was able to do everything else but running," Beltre said. "Taking ground balls, it started being back to the first time it happened. It was sore."
Beltre said he's never had issues with his calf muscles before.
Beltre hit .321 with 28 homers and 102 RBIs for the Red Sox in 2010.
In the Rangers' second intrasquad game Friday, Chris Davis played third base for a lineup made up of the expected starters. Davis also was in that role Thursday.
Washington said there is plenty of time for Beltre to get ready for the start of the regular season.
"We've had the conversation with Adrian to make him understand that the finish line is," Washington said. "The finish line is April 1, not Feb. 25."
Richard Durrett covers the Rangers for ESPNDallas.com. Information from The Associated Press was used in this report.