Drafted by Colorado in 2004, Fowler has spent his entire career with the Rockies. He joins a team that has posted three straight 100-plus loss seasons, including a franchise-record 111 losses in 2013 in its first year in the American League.
"There are definitely challenges, but at the same time you just got to look at the positives," Fowler said. "And the positive is that there are young guys here and they're eager to win and they're eager to put their (effort) into the game ... anything I can do to help, I'm just going to go out and play hard every day and I'm sure we'll definitely see the tides turn."
The speedy 27-year-old Fowler hit .263 with 18 doubles, 42 RBIs and 19 stolen bases in 119 games last season. Fowler, a switch-hitter who primarily plays center field, hit .300 in 2012.
"One of our goals this offseason was to bring in an outfielder who can spark our offense," Houston general manager Jeff Luhnow said. "Dexter is an exciting player who can help with the bat, with his legs, and with his glove."
Fowler missed a big chunk of the last month of the season with an injured left knee, but said Tuesday that the problem was behind him.
"I'm awesome," he said. "I'm healthy and ready to go."
Fowler hasn't had any extended conversations with Luhnow, but expects to play center field for the Astros next season and called the position "home." He isn't worried about navigating Tal's Hill in center field at Minute Maid Park.
"I played in the biggest yard in major league baseball, so I don't think anything is as challenging as Coors is," he said.
The Astros had the lowest payroll in the majors last season at less than $30 million. Houston owner Jim Crane said this offseason that he planned to start investing money into the payroll this season, and Tuesday's move is a sign that he was serious about that statement. Fowler is set to make $7.35 million next season before he is eligible for arbitration in 2015.
Fowler said he doesn't know any of the Astros players. He said he does know manager Bo Porter and is looking forward to playing for him.
Fowler is spending this offseason in Salt Lake City and said he'll train there until spring training because he and his wife are expecting their first child in January.
"She can't travel," he said, "so neither can I."
The 23-year-old Lyles was 7-9 with one save and a 5.59 ERA in 27 games -- 25 starts -- in 2013. He was a supplemental first-round pick by the Astros in 2008 and fills a need the Rockies have for a starting pitcher. Lyles made his debut at 20 and already has 65 career starts. He feels fortunate to have so much experience at such a young age.
"I'm going to continue to learn," he said. "I'll never stop trying to learn."
But he does know that pitching at Coors Field won't be easy.
"The park is obviously different," he said. "A lot of people don't like going there, but I'm up for the challenge and I think it's going to be fun."
Barnes, also 27, hit .240 with eight home runs and 41 RBIs as a rookie last season. He also became known for his knack for hustling to make great catches in center field.
"I'm excited for a new chapter and a new experience," Barnes said. "I've always prided myself on how hard I work and I plan on working really hard there and being a part of the Rockies' future and hopefully winning some championships."