According to Dejan Kovacevic, the Pittsburgh Pirates may have called up right handed pitcher Steven Jackson, and purchased the contract of left handed pitcher Justin Thomas. Thomas will take one of the two open spots on the 40-man roster, and the addition of both players will fill up the 25-man roster.
The Pirates still have no starter for Saturday, so my guess is that Jackson was brought up to help out the bullpen for the next two days, before a starter is needed. We will get an idea later tonight as to who the Saturday starter is. Charlie Morton was expected to pitch for Indianapolis tonight. If he pitches, then that pretty much confirms that Daniel McCutchen will start on Saturday. If Morton is held back, it gives a big indication that he is being held for Saturday.
Justin Thomas was originally claimed off of waivers by the Pirates at the end of October 2009 from the Seattle Mariners, and was designated for assignment on November 20th, so that he could sneak through waivers. Thomas put up a 1.30 ERA out of the AAA bullpen this year in 34.2 innings, with a 34:3 K/BB ratio. Thomas is under control for six seasons, and has two options remaining.
UPDATE 3:42 PM: The moves have been made official.