JUPITER, Fla. -- The Orioles finally decided to part ways with once-promising left-hander Matt Riley on Wednesday, sending the former prospect to the Texas Rangers for outfielder Ramon Nivar.

Riley, 25, lost out on the competition for the fifth spot in the rotation, and the Orioles had little recourse but to trade him because he was out of minor league options. When it was apparent Riley was not going to make the club, the Orioles began shopping him and found a taker in the Rangers, who are thin on pitching.

The final rotation spot was Riley's to lose and he did little to earn the job. He was 0-0 with an 11.57 ERA in five games and had been relegated to pitching in relief or minor league games the past few weeks.

"I'm not surprised," Riley said minutes after the trade was announced. "I'd be lying if I said I don't read around, listen for things. So I kind of knew something was going on with Texas. The main thing is that they are going to give me a shot over there, and that's all I can ask for."

Executive vice president Jim Beattie said Riley simply was a victim of unfulfilled expectations and a numbers crunch.

"He wasn't going to get an opportunity to pitch here," Beattie said after the Orioles' 5-5 tie with the Cardinals. "You stay with people and try to give them opportunities, but at the same time you are putting together a club that has the best chance to win. Unfortunately, Matt didn't fit in for us."

Riley was a third-round draft pick in 1997 out of Liberty (Calif.) High School and never panned out after being tabbed a can't-miss prospect. He made his Major League debut at age 20 Sept. 9, 1999, the youngest Orioles pitcher to debut in 32 years.

After making three appearances in 1999, he reported to Spring Training in 2000 with an attitude that angered many of his veteran teammates. The left-hander was also arrested for disorderly conduct at a Fort Lauderdale club during that spring.

Riley struggled with Double-A Bowie that season before he was diagnosed with a torn elbow ligament and required Tommy John surgery. Riley missed the 2001 season and returned to Bowie in 2002 to improve his arm strength.

He split the 2003 season between Bowie and Triple-A Ottawa and finally returned to the Major Leagues in Sept. 2003 and earned his first Major League win on Sept. 14 at Toronto.

Riley was named the fourth starter out of Spring Training last season, but floundered in that role. After a two-week stint on the disabled list in May, Riley was sent to Triple-A Ottawa, but he was given another chance to start in a July 3 game at Philadelphia.

Riley aggravated the organization by driving to Baltimore to hang out with friends a night before the game, and he didn't show up to Citizens Bank Park until 4:30 p.m. ET for a 7 p.m. game. He proceeded to allow five runs in one-plus innings and was banished to Ottawa until September.

He returned to the big club in September and went 2-1 with a 2.43 ERA in five games, giving the organization optimism for this season. Yet Riley let another opportunity slip away by getting off to a slow start in the spring, and he never made a serious run for the rotation.

"I just tried to work on some things this spring, try to elevate my game in a few areas and it cost me early," Riley said. "When I wasn't starting anymore, they were kind of letting me know they were headed in another direction. And I guess they felt like I didn't quite fit into the plan and I felt like I had a better opportunity to shine somewhere else."

Pitching coach Ray Miller, who was the Orioles' manager in 1999 when Riley was called up, said he was unimpressed with Riley's approach.

"He would have one good outing and two bad, just no consistency whatsoever," Miller said. "[Working on stuff in the early going] is not a very intelligent way to go about it, not when it's the last year of option. You come to Spring Training and say, 'Hey, I'm gonna make this club.' I don't know where he got that idea, I certainly didn't give it to him."

Riley will be tutored by Rangers pitching coach Orel Hershiser. He will compete with Pedro Astacio and Ricardo Rodriguez for a slot in the rotation.

"I am excited about [Hershiser]," Riley said. "I was a Giants fan growing up, and being able to watch him with the Dodgers and watch the way he pitched, I'm sure he has plenty of knowledge to help make me a better pitcher."

Nivas likely will start the season in Ottawa. He will join the team in Oklahoma City on Thursday. Coincidentally, he played for Triple-A Oklahoma last season.

Nivar hit .264 for the RedHawks with 10 homers and 52 RBIs. He was once considered a top prospect because of his speed, but scouts said he lacks baseball instincts. He was caught stealing 15 times in 30 attempts last season.

Mora hurt: Third baseman Melvin Mora could miss the next two exhibition games after being hit on the right wrist by a Jeff Suppan pitch in the third inning.

X-rays were negative and he will travel to Baltimore on Thursday to be examined by team doctor Charles Silberstein.

"Its a little tender I would think," Orioles manager Lee Mazzilli said. "I don't see any other reason for him not to be ready for Opening Day."

Also, Brian Roberts was OK after fouling a ball of his right leg in the ninth inning.

Tidbits: The club also traded catcher Keith McDonald to the Rangers for future considerations. ... Mazzilli also said B.J. Ryan will start the season as the closer. But he is unsure of a role for Jorge Julio. He is likely to announce other moves in Oklahoma City. ... The Orioles have added five minor leaguers to their roster for this weekend's games: infielders Bernie Castro and Tripper Johnson and outfielders Eugene Kingsale, Woody Cliffords and Nick Markakis. Pitchers Tony Fiore, Rodney Ormond, Tony Neal and Sendy Rleal will be added to the roster for Sunday's game at Philadelphia. ... Luis Matos was 1-for-1 with a double Wednesday and finished with a .386 average this spring, locking down the center field job.

Coming up: The Orioles travel to Oklahoma City to face the St. Louis Cardinals for the first of a two-game series. Right-hander Rick Bauer will start for the Orioles, followed by left-hander Bruce Chen. Right-hander Chris Carpenter will go for St. Louis.

Bauer has the inside track to the No. 5 starter spot, and Chen could crack the bullpen as a middle reliever.