With such a winding career path, spent in several different usage patterns, it's important to restrict our attention to -- or at least focus it on -- the Dennys Reyes the Cardinals have acquired, a knockout lefty with no legitimate claim toward versatility. The wonderful thing about looking at his career this way is that it makes sense of his late-career renaissance, which began with his gaudy 0.89 ERA in 2006. From 1997 to 2005, with interludes in LA and Kansas City as an inexplicable starting pitcher, Reyes was deployed as a more conventional reliever, with no more than vague LOOGY tendencies.
He was something of a victim of his own initial success, here; in 1999, his first full season with the Reds, he dispatched hitters indiscriminately, and faced fifty more right-handers. By 2001, even though he was now allowing a classically specialist .276/.378/.454 line against right-handed hitters, he was facing a righty two-thirds of the time. In 2005, his one year with the Padres, he allowed a .354 batting average against righties (.222 v. His Own Kind) and was dumped at mid-season.
As a rule I'm against pigeon-holing pitchers too early. They should be seen as starters until it's patently obvious that they're not, and they should face all kinds of hitters until the point is proven that they can't. But when Reyes was released by the Padres that July he'd made 344 appearances and was pushing thirty. In every year but two he'd shown a pronounced inability to retire right-handed batters, but it took until 2006, a year he began in the minor leagues, for somebody to limit his exposure to them. In 2006 he faced just two more righties than lefties; in 2007, twenty more left-handers; in 2008, fourteen.
If that's the Dennys Reyes the Cardinals want, they wisely looked past his early wanderings to determine that they could have him.
Until just now, I didn't realize that Reyes debuted in the majors just a few months after his 20th birthday. In 1997 he was the second-youngest player in the majors, and very nearly the youngest; he was just four days older than Andruw Jones. And it looks like Reyes is going to outlast Jones by at least a few years, because at 32 he might have another eight or 10 years in the majors if he can keep getting the lefties out.
I'm not a big fan of the whole LOOGY concept, at least not when taken to its extreme. But (1) Tony La Russa essentially invented the LOOGY, so presumably he'll get the most out of this one, and (2) if you're going to have one, you could hardly do better than paying $3 million for two years of a LOOGY with a 2.14 ERA over his past 126 innings. There have been some real bargains on the market this winter, and congrats to the Cardinals for finally jumping on one of them.