I'm just going to copy and paste the whole blurb from the player notes on CBS. It's easier that way.
News: Atlanta SP Tommy Hanson was scratched from Friday's start against Texas because of right shoulder tendinitis, according to the team's official website. Hanson, who fanned a career-high 14 batters in his last outing Sunday against Houston, has compiled an 8-4 record with a 2.48 ERA in 14 starts this season. The right-hander is also eighth in the National League with 89 strikeouts in 83 1/3 innings pitched. SP Randall Delgado is expected to make the start in Hanson's place against the Rangers.
Analysis: This development was certainly unexpected as Hanson had claimed three consecutive games and reported no arm troubles. He has not surrendered more than four hits over his last four starts and lowered his ERA to a solid 2.48 this season. It's unclear if the team will move him to the disabled list, but the Braves will certainly ease the 24-year-old back into the rotation when he's completely healthy.
Ugh, I hope it's not serious. I already have Josh Johnson on the DL - that would be my top two pitchers out. Fortunately, my starting pitching depth should (hopefully) keep me competitive.