LAKE BUENA VISTA, Fla. – Melvin Upton Jr. will likely miss all of spring training after being diagnosed with inflammation of a bone in his left foot, and the Braves suddenly have another opening-day spot up for grabs.

Upton had X-rays Friday morning that showed some damage but weren’t definitive, then had an MRI exam that revealed he has sesamoiditis, or inflammation in a bone behind the ball of his foot.

The Braves said he would be in short leg cast for two weeks, then a walking boot for 4-6 weeks. He’s not expected to resume baseball activities until early April. The Braves open the regular season April 6 at Miami.

Upton, who has struggled mightily in his first two seasons with the Braves, could be sidelined for the first month of the season or even longer, given how long he’ll be out of baseball activities. The Braves seem likely to turn to a current player or players in camp to fill in.

They acquired several players this winter who could be candidates to replace Upton including former Yankees prospect Zoilo Almonte, Eury Perez and veteran non-roster spring training invitee Eric Young Jr.

Almonte is more suited to play corner-outfield positions, but the Braves said when they signed him that he could play some center field. Young is also considered more of a corner outfielder and second baseman, but has plenty of center-field experience and would give the Braves a speedy, prototypical leadoff hitter they’ve lacked the past two seasons since Michael Bourn left as a free agent.

Perez, 24, is a speedster with plenty of center-field experience in the minor leagues but only brief callups with the Nationals and Yankees the past three seasons. The right-handed hitter had a .310 average, .371 on-base percentage, two home runs and 26 stolen bases in just 67 minor league games in 2014.

The Braves also have Todd Cunningham, who spent the past two seasons at Triple-A Gwinnett — .287 with a .347 OBP, eight homers and 19 stolen bases there in 2014 — and had eight plate appearances in 2013 in his only major league callup.

Recently acquired center-field prospect Mallex Smith, who led minor league baseball with 88 stolen bases in 2014, is also likely to get plenty of at-bats in spring training, though he is only 20, hasn’t played above Single-A and probably needs more minor league seasoning.

Upton was not available for comment Friday and will speak to reporters before Saturday’s workout, which starts three hours later (1 p.m.) than usual because the team is having its annual physical exams in the morning both days this weekend.

“I saw him limping around (Thursday),” Braves manager Fredi Gonzalez said after Friday’s workout, before learning the severity of the injury. Upton was held from the workout while being shuttled between doctors to have his foot examined.

Gonzalez said he spoke to Upton about the injury after watching him favor his left foot following batting practice Thursday in the team’s first full-squad workout.

“He came up to me after he hit and we sent him inside,” Gonzalez said. “He got treatment (Thursday), got treatment again this morning, and went to see the doctor to get X-rays.”

Upton hit .198 with a .279 OBP, 21 homers and 324 strikeouts in 1,028 plate appearances in his first two seasons of a five-year, $75.25 million contract, and the Braves tried this winter to trade him but could find no team willing to take on any significant part of the more than $46 million he’s still owed.

He announced upton reporting to spring training earlier this week that he would go by his birth name of Melvin Upton Jr., rather than B.J. Upton, which he’s used for his entire previous professional career.