He's been with the Orioles since the day he was signed by former Oriole pitcher Calvin Maduro out of Valencia, Venezuela in January 2010.
Reached by phone today in Binghamton, New York where the Double-A Bowie Baysox play tonight, Rodriguez said he was surprised by the news.
"They called me and said you got traded. I just have to keep doing my thing," he said. "My goal is to play in the big leagues, this doesn't change that. Just was very surprised."
After going 10-7 with an ERA of 3.41 last season between Single-A Frederick and Bowie, Rodriguez had made 16 starts this season for the Baysox and was 3-7 with a 4.79 ERA.
He said he got the news in a phone call from the O's executive vice president.
"Dan Duquette called me and told me," Rodriguez said. "He said thank you for everything you did for the Orioles.
"I've liked being with the Orioles but now I'm going to the Red Sox. I thank these guys for all they did for me."
Rodriguez is changing teams but not leagues. He said he will stay in the Eastern League and has been assigned to Double-A Portland. That means he actually could pitch against Bowie when Portland begins a series next Tuesday at Prince George's Stadium.
The Orioles signed Rodriguez for $175,000 in 2010, and he was rated as the club's No. 3 prospect last winter by Baseball America. Today, manager Buck Showalter said the O's had to trade quality to get quality back. Showalter praised Rodriguez and the club's player development system for producing a prospect that could bring a quality left-hander back.
Had he made the majors with the Orioles, Rodriguez would have become a real rarity - a Venezuelan amateur signee to make the big club.
After spending the last five seasons with the organization, Rodriguez said there is sadness in leaving the O's behind.
"Yes for sure," he said. "I'll miss everything."