2:35pm (update by Charlie): The Pirates have announced that the Phillies will receive righty Yoervis Medina in return for Biddle. After claiming Medina in December, the Bucs designated him for assignment last month and then outrighted him, so he clearly wasn't a high priority for them. Medina got good results as a reliever for the Mariners in 2013 and 2014, but struggled last season, both in Triple-A and the majors.
The Bucs also announced that they designated another player they recently claimed, A.J. Schugel, to clear space for Medina. Schugel really just looked like depth, and the likelihood is that nothing will amount from any of these moves. The Pirates originally cleared space for Schugel on their roster by designating Medina, which ... hey, we can go around in circles here all day.
11:52am: According to twitter reports linked at MLBTR, the Pirates have agreed to acquire LHP Jesse Biddle from the Phillies, although there's no official word yet. The Phillies designated Biddle for assignment recently. No word just yet on what the Pirates gave up, although it'll be a surprise if it was very much. Biddle is a long-term project: he had Tommy John surgery last fall and will miss the 2016 season, assuming Ray Searage is unable to make his new ligament become attached faster.
The Phillies had taken Biddle 27th overall out of high school in the 2010 draft. He was a regular on top prospect lists for a while, ranking as Philly's #1 or #2 prospect from 2011-13, and ranking as high as 71st, after the 2013 season, on Baseball America's top 100. He features a fastball that's sat anywhere from 88-93, to 92-94, along with a slider and change. He reached AA quickly at age 21, with high K rates that were well over a batter an inning in 2012-13. Control has been an issue, though, as he's walked 4.4 per nine innings in his career. The walk total got out of hand in AA in 2013, at 5.3 per nine.
Biddle has been plagued by injuries the past two years. He got a freak concussion in a hailstorm in 2014 and apparently continued to pitch through the symptoms, resulting in a demotion to high A. He mostly struggled at AA and AAA in 2015 and had the surgery after the season.
Biddle will probably spend 2016 on the 60-day disabled list, so he won't require a 40-man roster spot during the season. He'll need one now, though, so a roster move is still in the offing, as well as the question of the return to the Phillies.
UPDATE: Yoervis Medina, just outrighted to AAA by the Pirates, will go to Philly. That still leaves a need for a roster move.
UPDATERER: A.J. Schugel was dfa'd. The Pirates no doubt hope he'll clear waivers.