"Dan Otero...is an American professional baseball pitcher." So begins his Wikipedia entry. The Phillies are an American professional baseball team in need of some middle relief pitching, so the match between the two parties makes sense on a basic level.
But what sort of relief pitcher is Dan Otero? The easiest way to describe Otero's pitching is to say that, in a perfect and just world, he would be a career Minnesota Twin. He throws a fastball between 90 and 91 mph, though he usually relies on a sinker that made up over 60% of the pitches he threw in 2015. He also occasionally mixes in a changeup and slider.
Perhaps because of his reliance on the sinker, Otero has built a brief career as a moderately-effective middle reliever despite a near-complete inability to miss bats. He has a career K% of 14.1% and only induces swinging strikes on 6.6% of the pitches he throws. That sinker, by providing him with a career 54.9% ground ball rate, has allowed him to get by with unremarkable stuff. Opposing hitters hit that sinker on the ground on nearly 60% of balls put in play.
After releasing Justin De Fratus, the Phillies created a hole for themselves in the bullpen. While the likes of Dalier Hinojosa, Luis Garcia, Colton Murray, Luis Garcia, Hector Neris, an Nefi Ogando all represent internal candidates to fill that void, you can never have too much pitching, especially pitching of the relief variety.
While 30+ year old relievers are typically too expensive for teams at the Phillies' stage of development, Otero is still very cheap. He didn't make his major league debut until 2012, so isn't even eligible for arbitration until the conclusion of the 2016 season. Until that time, he will make something between 500k and 600k, which is just about as cheap as major league players get with the minimum salary in 2015 being $507,500.
I don't mean to imply that Otero is nothing more than a cheap warm body to absorb innings because, the fact is, he is probably ever so slightly more than that. His career ERA is an unspectacular, but inoffensive, 3.46. With career ERAs and FIPs about 10% better than league average, Otero should be able to provide the Phillies with a slightly positive contribution out of the bullpen.
Of course, Otero is coming off the worst season of his career. For the Athletics in 2015, he had an ERA of 6.75 (4.40 FIP) in 46.2 innings. That's the bad news. The good news is that projection models are largely writing that off as a fluke:
If he does that, which seems intuitively reasonable given his career numbers, he'll provide value to the Phillies for being able to not embarrass himself in 40-50 innings of work.
Matt Klentak was never going to make a trade for Mike Trout or the signing of Jason Heyward his first move as General Manager and this is about as far from a splashy first transaction as one can get. Nevertheless, claiming a cheap, reliable-ish reliever off waivers is a perfectly astute first move for his tenure.