Toussaint, 19 yesterday, looks like the headliner in this deal, as he was the Diamondbacks' first round selection last draft, and has already been pitching in Single-A, where he is the youngest player in the Midwestern League.
He has pitched to a 2-2 record with a 3.69 ERA in 39 innings, posting a 29 to 15 strikeout-to-walk ratio. Toussaint was rated No. 71 on Baseball America's top 100 prospects prior to this season.
The Braves also acquired Bronson Arroyo, a right-hander who continues to recover from Tommy John surgery. He is expected to return sometime this season. Arroyo's Tommy John surgery last season was the first time he had ever been on the DL in his career.
The acquisition of Arroyo, who is signed just through this year (barring a 2016 team option), looks like a way for the D-Backs to remove some salary from their books. Despite not the best pitching from their rotation without Arroyo, his loss won't be huge.
The dealing of Arroyo saves the Diamondbacks around $10 million, which they could put towards another trade at the Trade Deadline or a free agent signing later this year.
In return, the Diamondbacks get the utility man in Gosselin. The 26-year-old has 42 plate appearances thus far this season, slashing .325/.357/.425/.782 (117 OPS+). He will likely continue to serve in his bench role with Arizona.