Zimmerman and Suzuki on arrival of Nathan Karns

The Nationals were desperate to get something out of the fifth starter slot this week following the news left-hander Ross Detwiler has been placed on the disabled list with a right oblique strain. The franchise has decided to reach into their system and select Baseball America's No. 5 Nationals prospect to get a shot in the bigs. Manager Davey Johnson revealed after Monday's game that the 2012 Nationals minor league Pitcher of the Year, right-hander Nathan Karns, will be called up from Double-A Harrisburg to make his major league debut against the Orioles on Tuesday night. Karns went 11-4 with a franchise-best 2.17 ERA in 24 games (18 starts) for high Single-A Potomac and low Single-A Hagerstown in 2012. He led the organization with 148 strikeouts. Karns had a streak of eight straight wins from June 15-Aug. 2, 2012, sporting a 0.94 ERA. Karns was a 12th-round selection from 2009 out of Texas Tech. He recovered from right shoulder surgery in 2010 and made 13 starts in 2011 as he rehabbed back to 100 percent. In spring training, he did a good job for the Nationals. That is where catcher Kurt Suzuki got to work with him. "I caught him a couple of times," Suzuki said. "He has got a good arm. He has some good breaking balls. Obviously, spring training is really early, he is working on some things. Big-time arm, that is for sure." Karns has gone 4-2 with a 4.60 ERA in nine starts for Harrisburg. In three spring training games, he went 0-0 with a 2.45 ERA. Third baseman Ryan Zimmerman has not seen that much of Karns, but is confident in the depth of the system and knows the youngster has the stuff. "I know he throws hard," Zimmerman said. "Obviously, I haven't seen him pitch much. Our farm system is one of the reasons why we have been good the past two years because we have guys that can come up and make starts or guys that can help us continue to get better at this level. I am excited to see him pitch." Suzuki knows that for a rookie pitcher, making his major league debut can be a nerve-racking experience, and the key is to keep Karns on track during the start. "You try to make him as comfortable as possible," Suzuki said. "We will obviously go over the scouting report with (pitching coach Steve McCatty) before the game. When you go out there, it is all about feel. You can do all the scouting reports you want. You try to keep him calm, make him have fun out there. His first start, he is amped up, he is going to be nervous, but the more fun he has I think the better it will be." I asked Karns about being a possible sixth starter for the Nationals during spring training, and he said he was really more happy with finally being healthy and being able to just go out and pitch. Suzuki was impressed with the breaking pitches he saw from Karns in spring training. That was something then-low Single-A Hagerstown manager Brian Daubach told me about: opposing coaches complimented Karns on during games last season in the South Atlantic League. Last year was a breakthrough seasons for Karns, now he gets the opportunity to make an impression at the highest level Tuesday.