Nationals center fielder Denard Span underwent surgery Monday to repair what the team called a “right core muscle injury” and he will likely miss several weeks of the regular season.

It was the second surgery in three months for the team’s leadoff man, who led the National League with 184 hits last season. Span had sports hernia surgery on his left side in December, and he said in a text message Monday that there was a likelihood his recovery from the hernia surgery played a role in his new injury.

Washington can now reasonably envision an opening day lineup that does not include two-thirds of its projected starting outfield. Jayson Werth is still targeting April 6 for his return from January shoulder surgery but will not start throwing until next week. Nationals Manager Matt Williams said establishing a timetable for Span’s recovery is “probably premature,” though he did say one usually allots four to six weeks for similar injuries before a player can resume baseball activities.

“I’m frustrated that I’m going through this but glad that the surgery went well and is behind me so that I can move forward,” Span said via text message after the surgery. “Not 100 [percent] sure if the first surgery had anything to do with this but I think it did. Compensation played a some factor in re-injuring myself I think.”

According to Nationals General Manager Mike Rizzo, Span rehabilitated successfully from his December surgery. When Span got to camp, he felt discomfort on his right side but thought it would “work itself out.”

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“We kind of nursed him through it, and when he couldn’t by himself, we decided to get it taken care of and get it fixed,” Rizzo said. “He can take balls in the outfield, he can do batting practice, he can do all the things you do early in spring. It’s when your instincts take over and you do explosive movements that it comes into play. He felt he couldn’t do it.”

Span, who recently turned 31, has now undergone two surgeries on his core within three months. According to a league medical official, who spoke on condition of anonymity to speak freely about another team’s player, two such surgeries in such a short time frame is uncommon and cause for concern. Core muscles are not frequently operated on, he said, and while Span may be back doing baseball activities in four to six weeks, it will likely take longer to get back on the field.

“I bet you he’s not back before three months,” the medical official said, adding that Span perhaps wouldn’t feel fully healthy until the summer.

However long it lasts, Span’s absence leaves a void at the top of the lineup and in center field, one the Nationals plan to fill with Michael Taylor.

Taylor is the top position-playing prospect in Washington’s farm system, according to Baseball America. He will turn 24 later this month.

Rizzo said he met with Taylor a few days before news of Span’s surgery broke. “You’re the guy,” he said he told him. “We need you to prepare for that.”

Taylor started in center field and led off Sunday’s Grapefruit League game against the Yankees. He hit the first pitch of the game deep over the left-center field fence.

“Michael Taylor is one of the core players of the future, and the future is today instead of later on in his career,” Rizzo said.

Taylor made his major league debut last season and hit .205 with a home run and 17 strikeouts in 43 major league plate appearances.

“We’re certainly not comfortable without Denard, but it is what it is and you deal with these things all the time. We have experience — too much experience — of that from last year,” Williams said. “ With that being said, yes, we’re comfortable with Michael playing out there.”

Also available to fill in is left-handed hitting Tony Gwynn Jr., whom the Nationals signed last week. Gwynn can play all three outfield positions. Nate McLouth is another fill-in option, though he may be needed in left field if Werth is not ready. McLouth has yet to play in a spring training game, as he works through a throwing program as part of his rehabilitation from shoulder surgery in August.

James Wagner contributed to this report.