Urias spent most of 2015, his age-19 season, at Double-A Tulsa. He posted a 2.77 ERA and struck out more than a batter per inning over 13 starts there, though he was roughed up in two late-season outings at Triple-A Oklahoma City.
De Leon has raised his stock quickly since the Dodgers selected him in the 24th round of the 2013 Draft out of Southern University. Between Class A Advanced Rancho Cucamonga and Tulsa last year, he made 23 starts with a 2.99 ERA and nearly 13 strikeouts per nine innings.
Other non-roster invitees who ranked among the club's top 30 prospects in 2015 are righty Chris Anderson (No. 9), first baseman/outfielder Cody Bellinger (No. 10) and catcher Kyle Farmer (No. 28).
The Dodgers also extended invitations to righties Lisalverto Bonilla, Brooks Brown and Matt West, catchers Jack Murphy and Shawn Zarraga, infielders Charlie Culberson and Rob Segedin, infielder/outfielder Elian Herrera, and outfielders Corey Brown, Alex Hassan and Rico Noel.
Andrew Simon is a reporter for MLB.com. Follow him on Twitter @AndrewSimonMLB. This story was not subject to the approval of Major League Baseball or its clubs.