Two undefeated horses from two-time Triple Crown trainer Bob Baffert have again tested positive for a banned substance. Charlatan and Gamine -- both Preakness Stakes hopefuls -- tested positive for lidocaine in a second round of testing in Arkansas, according to the Associated Press. The initial positive tests came in late May.

Charlatan and Gamine tested positive for, lidocaine, which is the same banned substance they tested positive for the first time around. Lidocaine is known by the Association of Racing Commissioners International as a Class 2 drug. According to the New York Times and Louisville Courier-Journal, the first positive test on the horses came during a meet at Oaklawn Park in Hot Springs, Arkansas.

Lidocaine carries a penalty of a suspension of 15 to 60 days and a $500-$1,000 fine for the first offense. It is often used as a masking agent for other substances, which is why it has been banned.

Baffert released a statement saying that he believes that the horses were "unknowingly and innocently" exposed to lidocaine by one of his stable employees. He also claimed that the employee was dealing with back pain around May 2 after suffering a fractured pelvis. As a result, the employee wore a patch containing lidocaine and Baffert says that was how the horses were exposed to the banned substance.

"This is a case of innocent exposure and not intentional administration," Baffert said. "The extreme sensitivity of modern day testing can now pick up trace levels of innocent contaminants that have no effect on a horse. This is an issue that regulators of horse racing need to account for and address."

Charlatan earned $300,00 from winning a split division of the Arkansas Derby on May 2. The colt has been injured due to a minor ankle issue and was forced to miss the Belmont Stakes last month because of it. The injury will also keep the three-year colt out of the Kentucky Derby on Sept. 5, regardless of if there's a suspension for this positive test. However, Charlatan could still run in the Preakness Stakes on Oct. 3.

On the other hand, Garmine is a three-yeear old filly that tested positive shortly after winning the Arkansas Derby on May 2. In addition, the filly won her most recent race in the Acorn Stakes back on June 20. Baffert was considering running her in the Kentucky Derby, but her status could be in question after this second positive test.