(Photo credit: Naoki Fakuda) By Dan Ambrose: According to figthtnews.com, Promciones de Pueblo, representatives for middleweight challenger Marco Antonio Rubio (53-6-1, 46 KO’s), are saying that WBC middleweight champion Julio Cesar Chavez Jr. (45-0-1, 31 KO’s) failed to leave a urine sample for examination for performance enhancing drugs (PEDs) after last Saturday night’s fight between Chavez Jr. and Rubio in San Antonio, Texas. Team Rubio say that Chavez Jr. left without giving a urine sample.

In the past, Chavez Jr. was suspended after beating Troy Rowland in November 2009 after a diuretic, called “Furosemide”, showed up in Chavez Jr’s post-fight drug results. Diuretics are used for people to lose water weight. For a fighter who’s having problems waking weight, it could in theory help them fight in a weight class they can’t make weight for the normal way through dieting and exercise.

If what Rubio’s team says is true about Chavez Jr. leaving without having the drug test, it leaves open the question as to what happened. Drug testing are automatic parts of boxing now and it’s fairly rare that fighters fail to take them after fights. Rubio’s team wants Chavez Jr. to come back and be tested immediately are trying to get the World Boxing Council to enforce that. Will the WBC make Chavez Jr. come back to be tested is another question? How accurate are tests a day or more later?

Chavez Jr. weighed in at 181 pounds last night against Rubio, a gain of 21.5 pounds from his weigh-in weight the day before the fight. That’s a lot of weight but not an extreme amount. Rubio put on 12 pounds after the weigh-in and came in at 171. The middleweight weight limit is 160, and coming in at 181 the night of the fight, made Chavez Jr. in effect a cruiserweight in size in the ring.

Rubio was beaten by Chavez Jr. last night by a 12 round unanimous decision and had a lot problems with Chavez’s huge size in the fight. He simply wasn’t big enough and was roughed up and leaned on in close by the heavier Chavez Jr.

It’ll be interesting to see if the WBC will attempt to force Chavez Jr. to come back and take the drug test or whether they’ll ignore Team Rubio’s request or tell them it’s too late.