Phil Irwin did not appear in a game for Pittsburgh this year. (Getty)

PITTSBURGH -- The Pirates on Thursday designated for assignment right-hander Phil Irwin, a one-time top pitching prospect who has battled elbow problems most of this season.

Removal of Irwin from the 40-man roster cleared a spot filled by Josh Wall, a 27-year-old righty reliever claimed off waivers from the Angels and assigned to Triple-A Indianapolis.

"Phil's fastball velocity was down a touch, the consistency of the breaking ball was a challenge, the change has not come along as well as we had hoped it would," Pirates general manager Neal Huntington said in explaining why Irwin was chosen to make room for Wall. "The injury took a toll, but he's healthy now. We're just not seeing the same sharpness."

Irwin made his Major League debut in an April 17, 2013, start against the Reds at PNC Park, and he also spent a couple days with the Bucs earlier this month, without appearing in a game.

Irwin made 10 appearances, including two starts, this season for Indianapolis and compiled an 8.72 ERA in 21 2/3 innings.

Wall has had a checkered Minor League career, around sporadic big league appearances, since being a second-round pick by the Dodgers in the 2005 First-Year Player Draft.

In 10 seasons divided between starting and relieving, Wall has a Minors record of 41-48 with 35 saves. He posted 28 saves in 2012 with the Dodgers' Triple-A affiliate in Albuquerque.

"He's someone we've tracked for years," Huntington said, "and tried to get a couple of times and were not able to. We're taking a shot in the dark on a guy with a 95-96 mph fastball and a good hard slider. It was an opportunity to add a good arm to our system."

Wall has a Major League ERA of 15.15 in 15 appearances with the 2012-13 Dodgers and the Angels earlier this season.

"Given our needs, we thought Josh is a guy with a good arm who could help us this summer," Huntington summarized.

Cumpton looks to be frontrunner for rotation spot

PIT@BAL: Cumpton allows four runs over 5 2/3 innings

PITTSBURGH -- Brandon Cumpton appears to be the Pirates' pick to inherit Wandy Rodriguez's spot in the starting rotation, beginning with Monday's assignment in New York against the Mets.

The club did not reveal its plans in the wake of Rodriguez's designation for assignment on Thursday, but both manager Clint Hurdle and general manager Neal Huntington confirmed the choice was between Cumpton and left-hander Jeff Locke.

Locke took the mound as scheduled for Triple-A Indianapolis in Thursday night's game in Charlotte, meaning he would not be available to start on Monday. Cumpton, conversely, made his last start for the Indians on Tuesday, meaning he could step into Rodriguez's spot with only one extra day of rest.

However, not even these clues guarantee Cumpton's selection. Locke may simply be getting in some work to keep sharp, since otherwise he'd be asked to face the Mets with 10 days between starts.

In early organizational talks about the rotation's future, both pitchers had plenty of backers.

"The camp is as split as you can get," Huntington said early Thursday afternoon. "You heard, 'Brandon is throwing the ball great, doing things we love,' and, 'Jeff is back. The velocity has been better than a year ago, the breaking ball, changeup and command are all good.' So it's a really challenging decision."

The confidence in both pitchers made a quick call on Rodriguez easier. The lefty was designated about 19 hours after delivering the last pitch of his 1 2/3-inning start on Wednesday against Baltimore.

"We have two guys we feel completely comfortable about coming in and taking that spot," Huntington said. "Whether it's Brandon or Jeff, he will give us a legitimate opportunity to win the game. We didn't have that feeling with Wandy."

Either would have been a hot choice.

Locke spun one-hit ball for seven innings in his last start on Friday against Pawtucket. Those seven shutout innings lowered his ERA to 3.82.

Cumpton has been even more consistently impressive, sporting a record of 4-1 with a 1.35 ERA. Most recently, on Tuesday, he allowed a run and five hits in eight innings against Gwinnett. Cumpton also boasts the more successful recent big league experience. Including his two starts this season for the Bucs, he has a WHIP of 0.99 in his first eight Major League appearances.

Results show Davis settling in with Bucs

BAL@PIT: Davis belts a solo shot to cut into the lead

PITTSBURGH -- April can be a time of clean slates and fresh surroundings in baseball. And while that is usually the case in early April, Ike Davis got his scenery switched a few weeks later.

Davis was dealt to the Pirates from the Mets on April 18, and a little more than a month after the move, the first baseman is looking more and more at home with the Bucs. A 3-for-4 showing in Wednesday night's victory against the Orioles was the latest installment in a hitting tear the 6-foot-4 lefty has been on for a fortnight.

In his last 13 games, Davis is hitting .410 -- good for second-best in the National League since May 6 -- with a 1.079 OPS, and he's given the Pirates something they've longed for all season: production from their first baseman.

It wasn't always working out for Davis at the plate since he arrived in Pittsburgh. Despite starting out 5-for-14 in black and gold, Davis went into a slumber to the tune of a 3-for-32 stretch in 12 games from April 22-May 5. His slump featured 21 straight at-bats without a hit.

Davis has raised his averaged with the Pirates to .286 (it was .208 with the Mets), and manager Clint Hurdle said sometimes when little things fall into place off the field, it makes it easier between the lines.

"I do believe heavily in a comfort zone," Hurdle said. "For a week here, [Davis has] tried to figure out the soup kitchen guy's name, the clubhouse, how to get here, where he's living and play a game of baseball and teammates and the coaches. You can say, 'All you have to do is walk out there and play.' Yeah, that's part of it, but I do think it takes some time [to get comfortable]."

Worth noting

• After being activated off the disabled list, Russell Martin served his one-game suspension on Thursday and will be back in the starting lineup for Friday night's game against the Nationals.

Martin's suspension stemmed from an April 20 altercation with the Brewers, and it was upheld following a hearing on his appeal.

• On Wednesday, the Pirates were involved in a game in which neither their starter (Wandy Rodriguez) nor the opposition's (Chris Tillman of the Orioles) made it through two innings for the first time in their history. It was also a first in Interleague Play.

First number, last word

798: Major League managerial wins by Hurdle entering Thursday's game, two away from becoming the sixth active skipper with 800 (Bruce Bochy, Mike Scioscia, Buck Showalter, Terry Francona and Ron Gardenhire).

"I've tried to take advantage of each opportunity I've been given, and am grateful that Clint has stuck me back there for meaningful games ... it's been huge for me."
-- Tony Sanchez, whose tenure as the Pirates' primary catcher is about to end with the return of Martin.