RING middleweight champion Sergio Martinez has canceled Tuesday’s scheduled open workout for the media at his Oxnard-based training camp in the wake of threats against the fighter as well as an incident of vandalism that transpired over the weekend.

Martinez is preparing to meet WBC middleweight beltholder Julio Cesar Chavez Jr. (46-0-1, 32 knockouts) on Sept. 15 at The Thomas and Mack Center in Las Vegas.

“This past weekend, Sergio received threats from an unknown source, and the car in front of his home was vandalized,” said Lou DiBella, Mart├¡nez’s promoter, who has apparently spoken with local police officials regarding a situation which involved a team member’s car being covered in various colors of paint.

“Unfortunately, until we have a security team in place, we are going to have to suspend any and all public and media appearances for Sergio, including the upcoming media day scheduled for tomorrow in Oxnard. We apologize for the inconvenience to the media and fans that have planned on attending tomorrow’s event.”

DiBella seemed to believe that the incident is isolated, although he felt it was necessary to take precautions.

“When you say ‘security threats,’ it makes it sound like some international incident, and it wasn’t. Some idiots threatened Sergio verbally, and then, some idiot poured paint on one of Sergio’s team members’ cars that was parked right outside of Sergio’s apartment. We don’t think that any of Chavez’s fans are responsible, and we don’t think that it’s a Mexican or Mexican-American thing. We just think some idiots maybe had a beef, or some overzealous moron is involved,” said DiBella.

“But we don’t know. But there was a police report filed. This all just happened over the weekend, and really no one had any chance to address it until today. Tomorrow was too quick to make sure that there was going to be a workout that would have proper security in place. We’ve already got another workout scheduled, and we’ll do that next week. We’re counting on the fact that this is an isolated incident of stupidity, but you’re better safe than sorry these days.”

Martinez will making his first appearance in Las Vegas since February of 2000, when he was knocked out in the seventh round of a 148-pound bout by Mexican Antonio Margarito at the Mandalay Bay Hotel. The loss was Martinez’s first in 18 fights.

On Saturday night, HBO debuted an intense version of Face Off With Max Kellerman: Chavez Jr.-Martinez during which Chavez, 26, reminds Martinez of that devastating setback against Margarito.

Click here for a preview video of HBO’s Face Off, which will air multiple times on HBO and HBO2, with broadcaster Kellerman asking questions, face-to-face, of Chavez Jr. and Martinez.

After falling to Margarito, Martinez went 28-0-1, with 18 knockouts before losing a disputed majority decision to fellow left-hander Paul Williams in December of 2009, during which each fighter was floored in the first round.

Since losing to Williams, Martinez has won five straight bouts and four of them by brutal stoppage.

Former undisputed middleweight champion Kelly Pavlik, former two-time welterweight titleholder Williams and top contender Matthew Macklin were all left bleeding profusely around their eyes ears after facing Martinez. Williams was knocked out in the second round; Macklin in the 11th.

Previously unbeaten Darren Barker suffered a perforated eardrum during an 11th-round stoppage loss to Martinez, and previously unbeaten Sergei Dzinziruk was dropped five times during an eighth-round knockout loss.

The son of the former champion by the same name, Chavez Jr.is coming off a seventh-round stoppage victory over challenger Andy Lee in June.

Lem Satterfield can be reached at [email protected]