Birdsong is being evaluated for an elbow injury Thursday, Susan Slusser of The San Francisco Chronicle reports.
The nature of Birdsong's injury isn't clear, so it's unknown if this will be a long-term issue for the 24-year-old right-hander. He has been roughed up this spring, allowing eight earned runs on eight hits with two strikeouts and three walks across 2.1 innings. Even prior to the injury, Birdsong was viewed as a long shot to open the season in the Giants' rotation.