Patterson, 30, has had forearm problems dating back to the 2006 season, and two surgeries were unable to fix the problem.
"I started throwing about a month ago, and it hasn't been going well," Patterson said by telephone. "I have my good days and I have my bad days. So I decided to not play anymore. I'm going to retire."
Patterson played six seasons in the big leagues and was 18-25 with a 4.32 ERA during his career with the Diamondbacks, Expos and Nationals. His best season came with Washington in 2005, when he went 9-7 with a 3.13 ERA in 31 starts. He earned the nickname "The Big Nasty" after blanking the Dodgers, 7-0, on Aug. 4 of that year.
"That's a year I look back on and go, 'You know, that year really went right for me.' That's the way my career was supposed to be," he said. "I worked hard. I prepared myself. I didn't get the wins I should have gotten."
But it went downhill after the '05 season. Patterson would make just a combined 15 starts the next two years because of nerve damage in his forearm.
In 2008, Patterson proclaimed that his forearm problems were behind him, but he was hit hard during Spring Training and the Nationals released him on March 20. Patterson was 0-2 with a 7.00 ERA in nine innings, and opposing hitters had a .317 batting average against him. It didn't help that Patterson's fastball was clocked in the low to mid 80s. General manager Jim Bowden had said that he was looking for Patterson to have his fastball around 90 mph.
Three days later, Patterson signed a Minor League contract with the Rangers. Unfortunately, Patterson's forearm problems returned during an extended spring game in early May, and he was forced to miss the rest of the season. Texas released Patterson later that month.
Patterson was advised to rest the forearm until January 1, but he started throwing during the first week of December. The pain in his forearm returned two weeks later.
"It's just one of those deals where you scratch your head and ask, 'What went wrong?'" Patterson said. "I was taking care of myself and trying to do everything the right way. It just didn't work out for me. After time, it starts to wear on you.
"I'm tired of hurting. I'm tired of going through the pain and putting in the work. It's not moving forward. That's the best way I can say it to you. ... It's a tough decision for me. It was not a decision I wanted to make."
Patterson, a Texas native, declined to say what he was going to do with the rest of his life, but acknowledged that he has been doing a lot of hunting this offseason.
"There are a few things I have going here in town with a friend of mine -- business-wise," Patterson said. "Now that I have made the decision to move forward in my life, maybe some opportunities will open up for me. As of right now, it's up in the air."
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.