He played in Major League Baseball for the New York Yankees in 2004, for the Arizona Diamondbacks in 2005, and for the Oakland Athletics in 2006.

He then attended Hill College where he dominated with 11 wins along with his SS Dustin Murphy and many other players in Hillsboro TX.

[3] The New York Yankees selected Halsey in the eighth round of the 2002 Major League Baseball Draft.

[3] Halsey spent most of the 2004 season with the Columbus Clippers of the Class AAA International League, pitching to an 11–4 win–loss record with a 2.63 earned run average (ERA) in 144 innings.

[citation needed] Before the 2005 season, the Arizona Diamondbacks traded pitcher Randy Johnson to the Yankees in a three-team deal which also included the Los Angeles Dodgers.

Halsey entered the 2007 season as a candidate for the fifth starter slot, but did not pitch well in spring training, going 0–3 with a 6.75 ERA, and lost out to Kennedy.

[8] Halsey eventually did have surgery to repair a torn labrum in his shoulder on July 12, 2007, and was placed on the 60-day disabled list.

He signed a deal with the Long Island Ducks of the independent Atlantic League of Professional Baseball.

[3] Halsey threw a fastball in the 87–90 miles per hour (140–145 km/h) range, but his best pitches were a fine slider and a deceptive changeup.

They found Halsey walking in chest-deep water in the Comal River, referring to himself as Lucifer and talking about fighting someone named "Mitch".

According to the local judge who ordered the autopsy, Halsey's fatal injuries were caused by either a jump or a fall from a 100-foot (30 m) cliff on private property.

The Comal County Sheriff's Office believes that the fall was accidental, but kept the investigation open while awaiting the results of toxicology testing.