There could be other roster moves, as left-hander David Huff, who was called up on Monday, pitched one inning of relief and allowed two runs. David Aardsma, who has been the Triple-A Oklahoma City closer, has a June 1 out clause and the Dodgers reportedly have 72 hours to promote or release him.
Nicasio will be making his first start of the year against his former club, which traded him to the Dodgers in the offseason for Minor Leaguer Noel Cuevas. A starter with Colorado, Nicasio's longest outing this year is three innings.
The right-hander has a 1.29 ERA in 16 appearances, but Nicasio also has 11 walks in 21 innings, while left-handed hitters are batting .444 (8-for-18) against him and right-handers .088 (5-for-57).
Thomas was acquired last week from Atlanta in the Juan Uribe trade. He has made only one appearance for Oklahoma City, allowing six runs in 2 1/3 innings.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.