BALTIMORE—With the trade deadline 18 days away, Orioles general manager Mike Elias moved decisively to reiterate that the Orioles are still in the early stages of their rebuild.

Between games of Saturday’s doubleheader, the Orioles traded Andrew Cashner, who was scheduled to start Sunday’s game, to the Boston Red Sox for a pair of 17-year-old international prospects — outfielder Elio Prado and infielder Noelberth Romero. Both Prado and Romero will report to Orioles’ Dominican Summer League teams.

“Kind of a tough day for us saying goodbye to Cash,” Elias said. “He was terrific for us all year, a linchpin in the rotation and the clubhouse. I think it was a rejuvenation kind of year for him. I think he jelled really well with the coaching staff.”

Cashner, 32, was on a three-game winning streak and had a 9-3 record with a 3.83 ERA. He and John Means had been the team’s most reliable starters.

“We’ve made no secret of the fact that we’re eying our broad, long-term strategy, which is getting the best young talent we can from every angle, and there’s a trade deadline coming up. We had talks with several teams, and Boston was the most serious and most aggressive. We ended up getting two very young players that we like.”

Earlier in the day, the Orioles placed right-hander Dylan Bundy on the 10-day injured list with tendinitis in his right knee. Even though manager Brandon Hyde thinks Bundy’s absence will be brief, the Orioles’ rotation will be without established starters.

“It’s a huge hole in the rotation,” Elias said. “I think one way of looking at it is it will be more opportunities for young pitchers and fresh arms wherever we find one and it’s one more slot where maybe we will stumble into something that we’ll have beyond this year. It’s just one of those tough things we’ll have to do.

“Our guys will figure out a way to step up. It’s going to, especially in the short term, put a little more pressure on the guys that are here to cover innings.”

Cashner joins the reigning World Series champs, who are fighting for a wild-card spot.

“It’s a shocking moment, but I kind of saw it coming just the way our club is trending,” Cashner said. “I think it will maybe sink in tonight and once I leave tomorrow.

“It’s definitely exciting. I think that will more kick in once you get there. You make a lot of relationships in this game and just saying goodbye to a lot of people is maybe the toughest thing.”

Cashner can be a free agent after this season, and this trade is the first one in what promises to be an active market. The Orioles could also entertain offers for Bundy, reliever Mychal Givens, infielder Jonathan Villar and perhaps even outfielder/first baseman Trey Mancini.

“I don’t know if we’ll make any more deals,” Elias said. “I really don’t. I certainly am not adhering to the framework that they’ve got to be complex-level-age players. If it makes sense and we end up making a trade and a player close to the major leagues comes back. I just don’t know right now. We’ve got nothing else imminent, that’s for sure.”

Elias said the trade came together quickly, over the last week.

“I just felt like once we got a return that made sense, that was above the line, and able to get some young players with upside as opposed to getting players that were older or already on the 40-man roster,” Elias said. “Those are the type of offers you get. This is a tough trade market for getting young players. There’s a lot more risk with these types of players, but there’s more upside as well.”

Cashner will be back in Baltimore next weekend with the Red Sox, and though he had a horrible year last season with a 4-15 record and 5.29 ERA, his recent performance made him an attractive commodity.

“I think I’ve pitched great my whole career except for last year, so, I mean, I think teams kind of know what I’m about as far as grinding things out,” Cashner said.

Cashner now will call Fenway Park home.

“They’ve been a tough team to face, I know that,” Cashner said. “I think it will be really cool. It’s such a rich history of baseball with the whole … David Ortiz has been one of my favorite players growing up. Kind of getting to be around him from a different side. They’re still the champions from last year, so it will be fun to help them get to where they want to go.”

Red Sox president Dave Dombrowski said Cashner would start Tuesday against the Toronto Blue Jays.

“He’s excited to be here, excited to pitch,” Dombrowski said. “Excited to join the club and excited to be a part of the pennant race. As far as what we like, he’s been throwing the ball well … as well as he ever has.

“Definitely gives us an improvement in that fifth spot, where we scuffled for such a long time this year. … We like a lot of things about him. We think he makes us better.”

Cashner has a 55-82 record in his 10 major league seasons with the Orioles, Rangers, Marlins, Padres and Cubs. He is in the final season of a two-year, $16 million contract.

Baltimore agreed to send Boston $1,777,839 to cover all but $1,577,000 of the $3,354,839 Cashner is due from his $8 million salary this year. Baltimore also agreed to make contingent payments on some of Cashner’s performance bonuses if he should achieve them.

Romero and Prado, both 17, made their professional debuts in the Dominican Summer League. Romero, an infielder, hit .264 with two home runs in 29 games; Prado, an outfielder, hit .303 with nine steals and 26 runs scored in 33 games.

— ESPN.com contributed to this story