The Pittsburgh Pirates have made the signing of Jeff Karstens official, via a team press release. To make room on the 40-man roster, the team designated right-hander Zach Stewart for assignment. Stewart was acquired earlier this off-season for Kyle Kaminska.

The 2013 payroll page has been updated with Karstens' estimated salary.

UPDATE 3:15 PM: Will Graves reports the deal is for $2.5 M with $1 M in performance bonuses.

https://twitter.com/WillGravesAP/status/292001862738132992...

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