Allard was pitching at Triple-A Gwinnett in the Braves system and has been optioned to Nashville. But he is expected to get an audition in the Rangers rotation at some point this season.
"He's a young starter who already has significant experience at the upper levels," general manager Jon Daniels said. "His reputation as a competitor is well-known. We look forward to watching him compete as a Ranger."
The Rangers have had multiple discussions with the Braves with the approach of Wednesday's Trade Deadline. The Braves' farm system is deep in young pitching and the Rangers have their eye on right-handers Kyle Wright, Ian Anderson and Bryse Wilson in discussions for starter Mike Minor.
Instead the Rangers sent their most reliable reliever to Atlanta for the Braves' No. 10 prospect as ranked by MLB Pipeline. Allard, 21, was the Braves' first-round pick in the 2015 MLB Draft out of San Clemente (Calif.) High School.
There is still no indication if the Rangers will be able to trade Minor. But they are still planning to look at as many young starters as they can in the final two months of the season and Allard figures prominently on that list.
Allard has spent the season at Gwinnett where he was 7-5 with a 4.17 ERA and a 1.41 WHIP over 20 starts. He is averaging 9.7 hits, 2.9 walks and 8.0 strikeouts per nine innings. It was his second season at the Triple-A level.
Allard made three appearances for the Braves last season. He earned his first Major League victory in a spot start against the Marlins on July 31, allowing five runs, four earned, in five innings in an 11-6 victory. He also allowed seven runs in three relief innings over two appearances in August.
Allard's fastball averages at 88-93 mph but he commands the pitch well. Both his changeup and curve can be above-average.
"Not a big kid, but athletic," said one scout. "Young, a lot of success in the Minors, but probably rushed to the Major Leagues last year. He has a feel to pitch, starter repertoire, little curveball, a cutter and a good changeup."
Martin was 0-2 but with a 3.08 ERA and a 1.03 WHIP in 38 games. He is averaging 10.2 strikeouts, 0.9 walks and 8.3 hits per nine innings and was the Rangers' closer at the end.
With Martin gone and Shawn Kelley on the injured list, the Rangers could give Jose Leclerc a chance to be their closer again.