New York also sent cash to the Astros as part of the deal, completed one day before baseball's non-waiver trade deadline. Hawkins signed a $3.75 million, one-year contract with the Yankees last December.
"LaTroy gives us another experienced, quality arm for our bullpen," Houston general manager Ed Wade said. "We tried to sign him during the offseason and lost out to the Yankees, but we are happy to have him here for the remainder of the season. He gives (manager) Cecil Cooper one more weapon to call upon late in the game."
It was the second trade of the day for the Yankees, who also acquired star catcher Ivan Rodriguez from Detroit for reliever Kyle Farnsworth.
Wade said Hawkins will report to the team Friday, when the Astros open a three-game series against the New York Mets. Houston will be his sixth team in 14 major league seasons.
The 22-year-old Cusick was hitting .285 with nine home runs and 38 RBIs in 94 games for Class-A Lexington. The Astros selected him in the 10th round of the 2007 draft.
Wade said he's been looking for a reliever to ease the workload on pitchers such as Doug Brocail and Chris Sampson in the bullpen. The 41-year-old Brocail leads the team with 51 appearances. Sampson has made 21 relief appearances and 11 starts.
"We ended up getting a deal done for an experienced relief pitcher who we think can go back on the back end and help Brocail and Sampson and the other guys who we've been using late and help us get the job done," Wade said.
The Astros were 9½ games behind Milwaukee in the NL wild-card race entering Wednesday night's game against Cincinnati.
The GM said his discussions with the Yankees about Hawkins occurred within the last 24 hours. Wade said he talked to Hawkins, who lives near Dallas but has been working out at a college in Indiana since the Yankees cut him.
"He seemed very pleased with the opportunity he's going to get here," Wade said.
Hawkins is 57-77 with 75 saves and a 4.72 ERA in his big league career. He also pitched for Minnesota (1995-2003), the Chicago Cubs (2004-05), Baltimore (2006) and Colorado (2007).
Wade said he wanted to bolster his rotation and bullpen before the trade deadline. The Astros acquired starting pitcher Randy Wolf from San Diego last week and, after landing Hawkins, Wade said he's probably done dealing before the deadline.
"There is always the possibility that something else will happen," he said. "But realistically, this was the thing that's been teed up for a while here. We'll see what happens in the next couple of hours, but there is really nothing hot or active at this point."
