There might be a reason for that.
Zimmermann gave up eight runs on nine hits over three innings, while Karns surrendered seven runs (one earned) in just 2/3 of an inning.
According to manager Davey Johnson, both guys were battling medical issues.
For Zimmermann, it's merely a case of dead arm, according to Johnson, who said that the right-hander got treatment on his arm after the game. Dead arm often plagues pitchers as their arms get stretched out in spring, but they're usually able to pitch through it.
"I think it's about this time of spring," Johnson said. "All my pitchers go through a little dead arm. ... Nothing anything to worry about. Probably a little fatigue in there. But I see that third time out, sometimes fourth time out. Get that with everybody."
Zimmermann's fastball command just wasn't there today. He left the ball up over the plate, and Cardinals hitters made him pay, especially during a six-run third inning in which they bashed six hits, including three doubles.
"That's what happens when you're a little fatigued," Johnson said.
With Karns, it's a right leg issue. Karns, the Nationals' minor league Pitcher of the Year last season, felt some discomfort in the leg his last time out, a one-inning outing on March 2 against the Cardinals. The Nationals gave him an extra day of rest before his appearance today, but Johnson said that Karns' leg apparently "just doesn't feel right."
"I think we're going to probably have it checked further," Johnson said. "I said, 'How is your leg?' He says, 'It's fine. It's OK.' It's an issue. He's probably going to have the doctors check him.
"He said it was something he pitched with, but it's not normal for a guy to have to feel something uncomfortable in his right leg when he pushes off."
Karns looked really sharp in his first outing of spring, limiting the Mets to one hit over two scoreless innings and striking out three. Since then, he's walked four and allowed five hits in 1 2/3 innings over his last two outings.
"I'm concerned about it," Johnson said. "He's going to have further checking with the doctors before I run him back out."
Outside of the two injury issues, there weren't many positives for the Nats in a game that was 16-3 going to the bottom of the ninth.
"Wasn't pretty," Johnson said.
Wilson Ramos provided one of the few high notes from the Nats' regulars, singling in his only at-bat of the game and then proving his surgically repaired right knee is just fine by sliding into third to beat a throw after advancing on a ball in the dirt.
Ramos caught three innings today in his second outing behind the plate this spring.
"I thought it was a great slide," Johnson said. "I thought he was going to be out by a mile when he slid. He got a good slide. I was pleased with how he looked back there. It was like he caught for six innings with that (third) inning.
"I was just going to have him catch (four innings). But being down there and squatting that much I think nine hitters came to the plate or something and it was like catching four or five. But he came through it fine. Probably getting to the point where I'm going to alternate, I think. If Willy's alright tomorrow, get back to catching behind the dish every other day."