"[But] if we're going to trade one of those guys it's going to be a significant deal," Braves' general manager Frank Wren said. "And I don't know if that's going to happen or not."
Young starters Kris Medlen and Mike Minor aren't on the block though, O'Brien wrote.
Teheran and Delgado are expected to battle for the fifth-starter spot if they stick with the team.
Teheran, 21, is a 6'2" strikeout pitcher out of Colombia. He's been in Atlanta's minor league system since 2008, when he was 17 years old. In five seasons in the minors, Teheran has racked up a 3.50 ERA with a 8.1 K/9 in 514 innings.
He's spent the last two seasons in Triple-A, but struggled in 2012. After posting a 2.55 ERA in 24 starts at Gwinnett in 2011, Teheran's ERA ballooned to 5.08 in 26 starts last year. His hits per nine innings jumped from 7.7 to 10 last year, and his strikeouts dropped from 7.6 to 6.7 per nine innings.
Delgado, 22, has been on a similar path as Teheran. The 6'3" righty out of Panama spent most of his 2012 season with the Braves. In 17 starts, Delgado allowed 45 runs in 92 2/3 innings. He struck out 76 and walked 42.
Before the 2012 season, Teheran was rated the No. 5 prospect in the minor leagues by Baseball America. Delgado was No. 46.