SAN DIEGO - Antonio Bastardo wondered last summer whether he was better-suited for another team's bullpen, given the Phillies' glut of viable lefthanded relievers. The Phillies, on Wednesday, honored Bastardo's wishes.

They traded him to Pittsburgh for Joely Rodriguez, a minor-league lefthanded starter. Rodriguez, 23, should slide into triple-A Lehigh Valley's rotation and adds much-needed depth.

"Clearly we've been looking for starting pitching," Phillies general manager Ruben Amaro Jr. said. "We've talked about it several times. Starting pitching depth is a priority for us."

Rodriguez had a 4.84 ERA in 30 games (21 starts) at double-A Altoona in 2014. His strikeout rate declined at a higher level, and he allowed a great deal of baserunners. But he impressed after the season in Arizona Fall League play. He started seven games there and had a 2.38 ERA with 22 strikeouts and six walks against top-prospect competition. He is currently pitching in his native Dominican Republic.

Rodriguez's pitching coach in Arizona was Ray Burris, the Phillies' triple-A pitching coach. The team used those observations and other due diligence in evaluating Rodriguez. Amaro said Rodriguez's fastball sits in the low 90s but reached the mid-90s in Arizona.

"Good kid," Amaro said. "Good makeup kid, which is also a part and an element here, but also really coming on as far as his velocity and his stuff. All of those elements you like to see in pitchers as they mature and develop."

Bastardo, 29, was one of the team's better international success stories in the last decade. He signed for $7,000 in 2005 and became one of the league's most effective lefthanded relievers. But he was prone to command and mental mistakes.

"He was a major contributor for many years when we were having success," Amaro said, "and he was really gracious when we talked to him."

Since 2011, just three relievers - Randy Choate, Koji Uehara, and Craig Kimbrel - have held lefthanded batters to a lower batting average than Bastardo's .170. Amaro said there was "a lot of play on" Bastardo. Was this the best possible return?

"We felt like it was," Amaro said. "We were happy with it."

Bastardo is scheduled to earn nearly $3 million next season through arbitration.

"We've had a number of conversations about him and have tracked him for a handful of years," Pirates general manager Neal Huntington told reporters, "and feel like there's a good fit in our bullpen."