Frasor, 36, has a 3.34 ERA with a 1.38 WHIP and a 9.1 K/9 in 29 2/3 innings this year. He had a 2.57 ERA in 49 innings for the Rangers last summer. Frasor is owed roughly $900,000 through the end of the season and will become a free agent this winter.
The Royals have an elite setup man/closer combination in Wade Davis and Greg Holland, but the middle innings have been a bit of a problem. The club has reportedly been looking for bullpen help for the last few weeks and could continue to seek another reliever, specifically a lefty.
Patton, 26, has a 4.08 ERA with an 11.7 K/9 in 46 1/3 Triple-A relief innings this season. He was Kansas City's 24th round pick in the 2011 draft. Baseball America did not rank him among the team's top 30 prospects in their 2014 Prospect Handbook.
At 48-46, the Royals are 6.5 games back of the Tigers for the AL Central lead and 2.5 games back of the second wild-card spot. The Rangers have the worst record in baseball at 38-57 and figure to sell off more pieces before the trade deadline.