"I've always wondered," trainer Howie Tesher was saying, "how a ballplayer felt when he'd been traded and now he's playing against his old team."

Now Tesher knows: he wants to beat the devil out of them. That is how Tesher will feel when he saddles his new acquisition, John Speaks, against the horse he used to train, Tap Shoes, in Saturday's Flamingo Stakes at Hialeah.

If justice and handicapping logic prevail, John Speaks will win this important steppingstone to the Kentucky Derby.

A few months ago, Tesher thought Tap Shoes would be providing him with the greatest experience of his career: a genuine shot at winning the Derby. The colt had been hampered by bad conformation and an abundance of physical problems, but Tesher guided him delicately through a campaign that earned him a ranking as the second-best 2-year-old in the country.

For this, the trainer lost his job.

At the end of the year, Tap Shoes was sent for a rest to the Kentucky farm of co-owner Arthur Hancock. "Whenever I called the farm," Tesher said, "nobody would talk to me. I could feel it coming, like I was about to get a Dear John letter. Then one day I picked up the Racing Form and saw that Horatio Luro was going to train the horse. They didn't even give me the dimes back for my phone calls."

Hancock had decided to replace Tesher with the 80-year-old Luro, who won the 1964 Derby with Northern Dancer.

"I felt," Tesher said, "like Dick Howser must have felt when he won 103 games with the Yankees and lost his job. Luro has always been a friend of mine, and when I saw him I told him, 'If you win the Derby, I hope you'll do me one favor. Put on the winner's-circle photo: formerly trained by Howard Tesher.'"

Tesher managed to smile through this depressing experience, but he could smile in earnest after two horse owners he works for went looking to buy a stakes-class 3-year-old. It was on Valentine's Day that the trainer fell in love with John Speaks. He watched the colt win a nondescript allowance race and said, "When he made his move he exploded -- and only good horses do it the way he did." The owners bought John Speaks for $450,000, and quickly received a return on their investment.

In the Everglades Stakes last week, John Speaks made that big, explosive move on the stretch turn and took the lead, but was caught in the stretch by Highland Blade. His one-length loss was no disgrace. The time of the race was an impressive 1:48 3/5 for a mile and one-eighth, and John Speaks beat the rest of the field by seven lengths.

The colt still doesn't have the reputation of his three principal rivals in the Flamingo, Tap Shoes, Well Decorated and Dash O'Pleasure, but Tesher said, "If I had my choice right now, I'd take John Speaks."

John Speaks is the only one of the Flamingo contenders who has proved his ability to run the distance. Well Decorated failed badly in his two attempts at the mile last year. Dash O'Pleasure never has gone beyond seven-eighths of a mile and Tap Shoes is an uncertainty.

In the seven-furlong Bahamas Stakes at Hialeah, Tap Shoes came from far behind, finished strongly and lost by only a neck to Well Decorated and Dash O'Pleasure. Bettors will make Tap Shoes the favorite Saturday on the assumption that he wants to go a longer distance. But Tesher has his doubts. He thinks that the colt's poor conformation and awkward running style -- "he looks like Mark Spitz when he runs" -- will hurt him more as he tries to go farther.

John Speaks seems to have an edge in conditioning, distance-going ability and pure talent over his eight rivals and that should enable him to win the Flamingo's $108,600 first prize. To Tesher, the money is almost inconsequential. He probably would be willing to pay that much for the satisfaction of beating Tap Shoes.