The injury is near the top of Lucroy's hamstring, close to the hip, an area that had given Lucroy a little trouble at the end of last season, assistant general manager Gord Ash said Wednesday.
Lucroy said in a phone interview that the hamstring started bothering him when he pulled up quickly while running hard into third base during a game in August.
He said he has been diagnosed with a partially torn tendon, though "it sounded worse" than it felt.
Lucroy was fine when he was examined Jan. 26 in Milwaukee at the time of the team's winter fan outreach event, Ash said. The Brewers are unsure how Lucroy aggravated the injury.
Pitchers and catchers are scheduled to report to the team's spring training facility next week in Arizona. Ash said he was hopeful that Lucroy would be ready for the April 6 opener against Colorado.
"One thing we wanted to make clear here, he can still throw, he can still hit," Ash said.
Lucroy will also get more work on the practice field at first base, as the Brewers had planned, though he won't get game experience this spring.
The plan is to not run, Lucroy said, though he hopes to get into games at some point during spring training. He also is planning to catch in practice, given that he is already doing so now.
The injury doesn't change the long-term plans to get the right-handed Lucroy as many as 30 games at first base, Ash said. It's a way to keep his bat in the lineup while limiting his workload behind the plate.
Lucroy wasn't concerned the injury could affect how much time he will spend behind the plate or at first this year, given that he played with the injury last year.
Lucroy started 133 games at catcher last year, hit .301 with 13 homers and 69 RBIs, and finished fourth in voting for the National League MVP award. He was one of the few regulars in an otherwise free-swinging lineup who was able to consistently work counts.
Ash said Lucroy mentioned he had some concern about his right hamstring at the end of last season, and Lucroy told doctors that he was having trouble with the hamstring in November.
He was cleared in late January. The team said Lucroy's agent told general manager Doug Melvin last weekend that the hamstring was bothering him.
Lucroy was diagnosed with the injury by the team doctor Monday. Another examination Tuesday confirmed the extent of the injury.
Melvin is already in Arizona. Ash said his boss is optimistic and "pleasantly surprised" with the progress made by injured right-handed relievers Tyler Thornburg and Jim Henderson. Thornburg (right elbow) and Henderson (right shoulder) were each lost in the middle of the 2014 season.
"Given what we're seeing here, barring early setbacks, they're viable candidates," Ash said, "which is very good news for us."