Lowrie, a switch-hitter who has been injured often in his four-year Major League career, will become the Astros' starter at shortstop to replace Clint Barmes, who signed with the Pirates after one year in Houston. The move to the Astros gives Lowrie a chance to reunite with manager Brad Mills, who was Lowrie's bench coach with the Red Sox for two years.
"I'm excited," Lowrie said. "It's a great opportunity to reunite with Brad in Houston. I really enjoyed my time with him in Boston, and I'm looking forward to a great opportunity in Houston."
The Astros are getting a player in Lowrie who has struggled to stay healthy. A first-round pick by Boston in the 2005 First-Year Player Draft, Lowrie is a career .252 hitter with 19 homers and 117 RBIs in 256 games with the Red Sox since 2008. He batted .252 with six homers and 36 RBIs last season. "I think he's going to bring something to our ballclub," Mills said.
One thing Lowrie will bring is playoff experience, having helped the Red Sox reach the postseason in 2008 and '09. That will be important on a young Houston club that has inexperienced players all over the diamond as it continues to rebuild.
"I had a couple of years of playoff experience in Boston, and I think it was an opportunity for me to learn what it's like to be on the biggest stage in baseball," Lowrie said. "Now I want to bring that experience to Houston and that culture of a winning attitude to Houston. Even if a team is -- quote, unquote -- rebuilding, it's about winning. I'm going to do everything I can to help the Astros win."
Lowrie doesn't possess great range at shortstop, but his strength is his ability to hit left-handed pitching. He's a career .326 hitter with a .385 on-base percentage against left-handers, but against right-handers is just a .214 hitter with a .293 on-base percentage.
"If you look at my stats, especially through the Minor Leagues and back to college, almost all of my production came from he left side of the plate," Lowrie said. "I know I can hit from the left side. I've had a couple of injuries that have affected my left-handed swing. I'm not here to talk about that. I'm here to talk about the fact I know I'm a quality hitter from both sides of the plate, and I'm going to do the work necessary to get myself ready to be what I believe is a .300 hitter on both sides of the plate."
Weiland, a third-round pick of the Red Sox in the 2008 Draft, will compete for a spot in Houston's rotation. He made his Major League debut in '11, but struggled in limited time as a spot starter and reliever. Weiland, who started five games in seven appearances, went 0-3 with a 7.66 ERA in 24 2/3 innings, with 13 strikeouts and 12 walks.
"I've never been traded, obviously," Weiland said. "It came as a surprise to me, but at the same time, it's a great thing because when you get the call you're going to a place that's looking to have you and use you. That's why they traded for you. It's a great opportunity. I'm going to get the chance to earn a roster spot, but nothing is going to be handed to me."
Weiland will be among a handful of players competing for a starting spot in Houston's rotation next year, a list that includes Jordan Lyles, Henry Sosa and Lucas Harrell.
"Any time you've got a guy's arm like [Weiland] has and what he's able to bring to the table, we want to give this guy a chance to put some innings in for us and utilize his stuff," Mills said.
Melancon, 26, could fill Boston's need for a closer. He pitched in a career-high 71 games for the Astros last season and was 8-4 with a 2.78 ERA and saved 20 games. Mills said it's too early to address the team's closer situation for next year, but veteran Brandon Lyon should be healthy after missing most of last season with a shoulder injury.
The Astros acquired Melancon from the Yankees at the Trade Deadline in 2010 as part of the Lance Berkman deal.
"For me, it's the classic win-win trade," Luhnow said. "Boston had the need for a bullpen arm. We're going to suffer a loss in our bullpen by not having Melancon there for us, but what we're able to get back is a guy who can play a premium position and who has had success with the bat and who has done a lot of good things. To add on top of that a young pitcher capable of being a starting pitcher in the big leagues, we felt this is an opportunity to take advantage of."
To make room on the 40-man roster, the Astros designated infielder/outfielder Brian Bixler for assignment. Bixler was acquired off waivers from the Nationals last month after appearing in 79 games for Washington, hitting .205.