It was a relatively uneventful morning for the Repole Stable duo of UNCLE MO (Indian Charlie) and STAY THIRSTY (Bernardini), who went trackside at 8:30 a.m. (EDT) during the special Derby/Oaks training period and galloped 1 3/8 miles under their regular exercise riders -- Hector Ramos on Uncle Mo and Fernando Espinoza on Stay Thirsty.

But outward appearances can be deceiving and behind the scenes at trainer Todd Pletcher's Barn 34 the wheels were turning and churning on a scenario that might rob Derby 137 of its "name" horse.

Uncle Mo, the colt who won all three of his starts last year -- including the Breeders' Cup Juvenile (G1) run at Churchill Downs -- and was named two-year-old champion, has had a not-so-dominant three-year-old season thus far. He won a less-than-competitive overnight stakes at Gulfstream Park in March, then was a beaten third in the Wood Memorial (G1) in New York on April 9, after which he was diagnosed with a stomach ailment that required antibiotics for treatment.

And while reports out of the Uncle Mo camp have been generally positive over the past several weeks as he has trained up to the Kentucky Derby (G1) at Churchill Downs, the doubts about his "real" condition linger and they were coming to a head Thursday.

Owner Mike Repole addressed a gathering of about three dozen media types at approximately 9:30 a.m. Thursday outside Barn 34 and spoke of the quandary that he and Pletcher have concerning their star.

"When I see him on the track, like I saw him this morning, I say he's doing super, he's doing great, he moves like the best athlete on the track," the New York businessman said. "But I'm not the expert and we just aren't sure here where this horse is. Is he back to 80 percent of himself; 90 percent, 100 percent? We don't know. If this was an 'outside' issue, you probably could be sure of what you're dealing with. But this is an 'internal' thing and they're much harder to tell.

"So today we're having three veterinarians go over him and test him and we're going to make a decision. Dr. (Ken) Reid, Dr. (Steve) Allday and Dr. (Doug) Byars are going to check him out and test him and give us their opinions -- whether we should run him or not.

"Todd (Pletcher) and I will be involved in the final say. Todd will be the real key for me. If the three vets said go ahead and run him, but Todd voted no, then we wouldn't run. He's the guy.

"Probably by the end of the day we'll know what we're going to do. We'll know for sure by the morning. And we won't wait until Saturday to make a decision. We'll say tomorrow, one way or another.

"If he doesn't run, I don't know what the plan will be. We'll have to let Uncle Mo tell us what is next."

Uncle Mo drew post position 18 in the Derby lineup and is scheduled to be handled by his regular rider, John Velazquez. Stay Thirsty will start from post position four under Ramon Dominguez.