6. Nate Karns
Nate Karns was taken in the 12th round of the 2009 draft by the Washington Nationals. He made his way to the major league team in 2013 at the age of 25 without ever pitching in Triple-A. He only logged 12 innings with Washington but in his 132.2 innings in Double-A he posted a 3.26 ERA and struck out 155 batters.
Prior to the 2014 season, the Rays traded Jose Lobaton, Felipe Rivero, and Drew Vettleson for Karns. He finally got his opportunity to face Triple-A hitting in Durham.
The Rays loved his electric arm and flaming fastball, but he struggled with command. He finished the 2014 season with a 5.08 ERA. He did make two appearances with the Rays that season.
At the age of 27, Karns started 26 games for the Tampa Bay Rays in 2015 and went 7-5, posting a 3.67 ERA. He struck out 145 batters in 147 innings as a major leaguer.
Heading into the 2016 season, the Rays had a bit of logjam at starting pitcher. It appeared Karns would be destined for a bullpen role so they club decided to trade him, coming off of his successful 2015 campaign.
There was concern about Karns’ health at the end of the 2015 season as suffered forearm tightness.
Karns appeared in 27 games for the Mariners the following season and posted a 5.15. ERA. The Mariners traded him to the Royals following his disappointing season.
Karns made eight starts for the Royals before a forearm injury ended his season. He wouldn’t play another major league game until last season. Karns pitched in 5.1 innings with the Orioles. Karns again missed the majority of the 2019 season due to a forearm injury.
Karns, 32, is currently listed as a free agent.