Washington starter Stephen Strasburg talks with pitching coach Steve McCatty after his seven-inning outing in a 4-2 loss to St. Louis. (John McDonnell/The Washington Post)

The biggest single reason Stephen Strasburg lost his fourth straight start on Wednesday as the Washington Nationals fell below .500 is because he won’t throw “strike one.” He can. But he doesn’t. He says he will. Then he backslides. He talks about pitching to contact, quick outs, efficiency and going deep in games, then does the one thing that negates all of it: “Ball one.”

“I was trying to throw the perfect pitch. I tell myself, ‘Don’t do that.’ Then I go out there and do it,” a disgusted Strasburg said of a three-run first inning in a 4-2 defeat to the St. Louis Cardinals. Falling behind hitters and “trying to do too much” has been Strasburg’s recurrent complaint against himself through the first four-game skid of his career. But then he does it again.

Strasburg fell behind four of the first five Cards hitters, had to throw strikes on the hitter’s terms and saw the game lost when it had barely begun. The worst thing a team in a hitting slump can endure is an early deficit before it even gets to bat. Asked to be an ace, Strasburg dealt a trey.

The Cards’ rally was built on a walk and two opposite-field chunk hits dumped in front of outfielders. “You saw it. Weak contact, what can you do,” Strasburg said. Most pitching coaches of the last 100 years would say, “Throw strike one.” Then hitters will not get a free chance to look for a specific pitch in a particular zone and drop an ugly duck snort over the infield.

In 2011, Strasburg threw first-pitch strikes 71.6 percent of the time, the highest in baseball. He carried over his “challenge” mentality from college and put fear of shame into hitters. Last year, he threw 62.3 percent, 34th among starters. Wednesday, he was down to 56.2 for the season, an awful 84th among 107 starters.

The Post Sports Live crew discusses whether manager Davey Johnson bears the responsibility for the Nationals’ slow start to the season. (Post Sports Live)

How can the pitcher with, perhaps, the best four-pitch stuff of his generation — any one of which he can use to challenge hitters with arrogance if not impunity — shy away from contact on the pitch which, if it’s a strike, opens the door to outs? Every year, the average on-base-plus-slugging percentage in MLB is more than 100 points lower after 0-1 counts than 1-0. Everything else in pitching is hard. “Strike one” is lesson one on day one.

Strasburg’s first-pitch issues are especially important because they typify the Nats’ starting staff across the board. This lack of aggression, a failure in many cases to make full use of some of the game’s most dominant stuff, may be the Nats’ biggest pitching problem. Perhaps it’s even a symptom of a team that has gone from being the hunter to the hunted. Jordan Zimmermann’s percentage of first-pitch strikes has dropped from 69 to 55 percent, Dan Haren from 64 to 55, Gio Gonzalez from 59 to 55 and Ross Detwiler just a tad from 61 to 59.

The data sample may be smallish, but the pattern is uniform. Some Nats may be prospering now, but no pitcher wants to give away his first-pitch edge for long. Strasburg matters most because his potential is greatest.

Until he gets his 0-0 phobia fixed, until he reverses the balance of terror between him and hitters, getting back to the level of confidence he showed when he arrived in the majors four seasons ago, he’s going to be a very good pitcher who doesn’t go as deep into games as he’d like.

Hitters have adjusted to Strasburg by swinging early in the count, especially at his fastball — not because it is easy to hit but because his curve and change-up are wipeout strikeout pitches, especially with two strikes. The logical response to this is: Go ahead and try to hit a 95.7-mph fastball, the quickest average of any starter by more than 1 mph. Good luck. Some will get hits. Many will not. And at-bats will be resolved quickly.

Instead, Strasburg, even though he hit 98 mph on Wednesday, appears cautious about first-pitch ambushes that lead to hits, forcing him to pitch from the stretch where he isn’t quite as fast and has to cope with base stealers. By aiming for edges, shying from the bat, he merely forces himself to make the same pitch on 1-0 or 2-0 or 2-1, when the hitter has more options, that he could have made on 0-0. Attack isn’t a perfect method but, with Strasburg’s stuff, it has every inherent advantage.

Strasburg sometimes has trouble analyzing his problems or tweaking mechanics in the middle of innings because he can’t seem to slow himself down. A bad pattern repeats, often producing 30-plus-pitch innings until he gets back in the dugout and thinks. Then his analytical nature and discipline usually fixes the issue. If he ever learns to do it on the fly, watch out.

After the first inning, Strasburg apparently gave himself that internal lecture. He stopped trying to throw perfect pitches, especially on 0-0, and instead threw strikes with his overpowering stuff. On the last 20 hitters he faced, he threw 75 percent strikes, a huge percentage, and got 20 outs.

“After the first inning, he made it look easy,” Nats Manager Davey Johnson said.

That’s because it was.

Strasburg’s April troubles and the Nats’ five-game deficit to the Braves in the National League East should produce an interesting reaction from Washington fans, despite the lessons of the last year. The Redskins started 3-6, were universally pronounced dead, then finished 7-0 to take the NFC East. The Wizards started 4-28, were declared one of the worst NBA teams ever, then played .500 ball thereafter. When the Capitals had the worst record in the NHL, the general manager was under fire and Alex Ovechkin was washed up. Tuesday, the Caps clinched the Southeast Division and the No. 3 seed in the Eastern Conference for the playoffs.

Everybody wants to win every game. But it’s not how you start. It’s how you finish. So you’ll excuse the Nats if they note the 141 games they have left, even as they criticize themselves for their pressing play.

“We’re just goin’ through it right now. Can’t get a break. It’s laughable at times. Denard Span hits a bullet and its like [Jaime] Garcia’s glove has a magnet in the pocket,” Jayson Werth said. “We need to jumble it up and we need to switch the mojo a little bit. I think somebody was talking about Phil Jackson the other day. We need to call him up, have him come in here and burn some sage or something.”

Then Werth grew serious. “This team has a lot of guys that are . . . I can’t use the term,” said Werth, who then did use the words, the same ones that Jules Winnfield had stitched on his wallet in “Pulp Fiction.”

“That’s who we are and that’s what we’ve got. When we get up in big situations, we want to do it,” Werth said, meaning do damage, not poke a single to the opposite field. “That’s a double-edged sword for sure. That’s the classical way to press.

“My last at-bat, I said, ‘I just swung too hard.’ I took a little off, softened it up,” said Werth, who then homered into the bullpen. “ ‘Boom.’ That’s always the way.” So, he mentioned it to Ian Desmond and others. After Tuesday’s loss, several Nats stayed late for a mutual gripe session about the evil bounces of the baseball. Now, they may use the “try easier” speech. Whatever it takes until something clicks.

“We wanted those high expectations to be on us. We played for it, busted our butts to get it last year,” said Desmond. “Now it’s 2013 and only April. . . . The grind is what we play this game for.”

For previous columns by Thomas Boswell, visit washingtonpost.com/