Halsey was an eighth round pick in 2002 for the New York Yankees, and made his debut for them in 2004. He came to Arizona in January the following year, being part of the deal which sent Randy Johnson back to the desert, and joined the Big Unit in the Diamondbacks 2005 rotation. Halsey appeared in 28 games for Arizona that year, and began well, going 4-2 with a sub-three ERA over his first 10 starts. He faded thereafter, ending the season 8-12 with a 4.61 ERA (which in those days was good enough for a 96 ERA+). His best start came on May 31, back in New York against the Mets, when he wen seven shutout innings, allowing six hits and a walk with six strikeouts.
Just before Opening Day 2006, he was traded to Oakland for reliever Juan Cruz, and appeared in 52 games for them, both as a starter and out of the bullpen. That was his last stint in the major leagues, but he stayed in the game for a while, playing both indie ball and back in the Yankees farm system, most recently for Double-A Trenton in 2011. Career highlights included starting the game for New York against Boston, where Derek Jeter dove into the stands, and giving up Barry Bonds' 714th HR, tying Babe Ruth. He said of the specially-marked balls used for the latter, "They just have a B and a number on them, and a picture of Barry, too. If you look into his eye, he winks at you."
I leafed through the SnakePit archives to see if we wrote anything worth reprinting about Halsey. The truth is, no. The closest was probably this: "The words 'Russ Ortiz' and 'quality start' go together about as well as 'Brad Halsey' and 'quality at-bat'". Checking the stats, Halsey was a bit of a rabbit: his .063 average is third lowest all-time among players with 50 PAs for us - as a yardstick, it's 13 points lower than Brandon McCarthy. It seems disrespectful to remember him for that, so let's instead, remember Halsey's start for the Diamondbacks on May 20, 2005, when he faced Roger Clemens and beat him.
"All credit to Halsey, who was given a first innings opportunity by a combination of good hitting and inept defense, and locked onto it with a death-grip. You could not have pried that victory from him if you'd cut Halsey's head off."
Our sympathies go to his family and friends.