Brubaker and Helton, both drafted as juniors, will report to short-season Low A West Virginia, while McGarry will report to the Gulf Coast League Pirates in Bradenton, Fla.
Brubaker went 5-4 with a 3.63 ERA in 15 starts as a junior this spring, leading Akron in strikeouts (72), while finishing second in wins and innings pitched. The slot value for his pick, 187th overall, was $246,500.
McGarry went 4-1 with a 2.25 ERA in 21 relief appearances as a junior this year for FAU. Picked with the 247th overall selection, McGarry was ranked by MLBPipeline.com as the Draft's No. 147 overall prospect. The slot value for his pick was listed at $168,800.
Helton, the son of two-time Super Bowl champion Barry Helton, went 2-8 with a 5.72 ERA, 48 strikeouts and 32 walks in 61 1/3 innings over 18 appearances for Utah this spring. Helton agreed to a $150,000 signing bonus, according to a source. The 277th pick's slot value was listed at $157,600.
Adam Berry is a reporter for MLB.com. Follow him on Twitter at @adamdberry. This story was not subject to the approval of Major League Baseball or its clubs.