Paterson was released by the Royals on Thursday, Matthew DeFranks of Fox Sports Kansas City reports.

Paterson signed a minor league contract with the Royals in November with an invite to spring training, but failed to make the team out of camp. The lefty struggled with Triple-A Omaha as he posted a 5.68 ERA in 12 appearances this season, and will likely have to settle for a job in the minors again wherever he signs on next.

Paterson signed a minor league contract with the Royals on Wednesday that includes an invite to spring training.

While Paterson posted a career-worst walk rate of 4.0 BB/9 in 56 appearances with the Diamondbacks' Triple-A Reno affiliate in 2014, resulting in an unsightly 1.50 WHIP, he held opposing lefties to a .198 BAA. He will get to make his case for a specialist role in spring training, but Paterson need to perform at a high level in order to earn one of the Royals' final bullpen spots.

Paterson was recalled from Triple-A Reno on Friday.

Paterson will add an extra arm in the bullpen for the remainder of September and could use it as an audition for the 2015 season. He will likely serve in middle relief for the Diamondbacks when used.

Diamondbacks optioned LHP Joe Paterson to Triple-A Reno.

The 27-year-old southpaw had been a longshot to earn a bullpen job out of spring training. He'll continue to function as organizational depth, and should see time with the Snakes at some point during the upcoming season.

Diamondbacks optioned LHP Joe Paterson to Triple-A Reno.

The move clears a spot for Aaron Hill's return from the disabled list. Paterson made two appearances with the Diamondbacks and will return to a 2.36 ERA at the Triple-A level.

Diamondbacks recalled LHP Joe Paterson from Triple-A Reno.

He'll serve as the second lefty in the pen while Matt Reynolds is out. Paterson held a 2.36 ERA while striking out over a batter per inning at Triple-A before his recall.

Diamondbacks optioned LHP Joe Paterson to Triple-A Reno.

Diamondbacks recalled LHP Joe Paterson from Triple-A Reno.

Paterson was a key piece of the big league bullpen in 2011 but was a mess in his short stint with them this year. He'll try to win a spot in the pen next spring.

Diamondbacks optioned LHP Joe Paterson to Triple-A Reno.

Paterson has surrendered 15 hits and 11 runs in just 2 2/3 innings this season. The Snakes will hope for better out of left-hander Mike Zagurski, who was recalled from Triple-A Reno in a corresponding roster move.

John Gambadoro of 620 KTAR expects lefty reliever Joe Paterson to be demoted to Triple-A Reno.

He's hardly going out on a limb there, as Paterson has allowed 11 runs on 15 hits and three walks over just 2 2/3 innings this season, resulting in a stunningly bad 37.13 ERA. Gambadoro also expects left-hander Mike Zagurski to take his place on the roster.

After entering with a 9-0 lead in the ninth, Joe Paterson gave up five runs without retiring a batter Monday against the Phillies.

Shane Victorino and Carlos Ruiz hit back-to-back homers off him. Paterson did nice work as a lefty specialist for the Diamondbacks as a Rule 5 pick last year, but this is the fourth time in six appearances this season that he's been charged with at least one run. Overall, he's allowed a whopping 15 hits in 2 2/3 innings. A demotion to Triple-A is likely in the cards.

Nick Piecoro of the Arizona Republic hears that left-hander Joe Paterson has made the Diamondbacks' Opening Day roster.

Paterson, a Rule 5 pick, has posted a 5.40 ERA and 12/4 K/BB ratio over 10 innings this spring. If he makes the team, the final spot in the bullpen will likely come down to Esmerling Vasquez or Kam Mickolio.