Chad Tracy spends a few moments on the field most nights, if he emerges from the Washington Nationals dugout at all. Manager Davey Johnson holds him in reserve until a single swing may shift the outcome. Tracy almost always enters the game for one at-bat, and one at-bat only. He usually does not play defense. He sometimes does not run the bases. And at the end of the night, he leaves the ballpark completely exhausted.

The apparent simplicity of Tracy’s job is a disguise. It belies the work he devotes to every pinch-hit chance, the seven hours of preparation that produce two minutes of performance.

Tracy has become a valuable, unheralded piece of the first-place Nationals’ success not because of what he does on the field, under the lights. He thrives because of his daily regimen in a batting cage under the stands, the steady routine, careful study and intricate timing that lead into every precious at-bat.

“You’re mentally drained after the game,” Tracy said. “You may not be as physically drained as the guys playing out there. Mentally, just trying to figure when you’re going to go in the game and make sure you peak at the right time.”

Tracy signed a minor league contract with the Nationals this winter, after an injury-plagued season in Japan. General Manager Mike Rizzo had drafted Tracy when he worked for the Arizona Diamondbacks, and he still believed Tracy could help his bench. Last month, the Nationals rewarded him with a $1 million contract extension for next season.

At this stage of his career, Tracy, 32, has embraced his role off the bench. For younger Nationals’ bench players, such asTyler Moore and Steve Lombardozzi, he serves as something of a guru. “He just kind of gives us a confidence,” Moore said. He shares with them his insight into pinch hitting, which he honed over several seasons.

“It did not come naturally,” Tracy said. “Usually, when I was sitting the bench early on, I was not happy. It was kind of like an angry at-bat — go up there and swing hard three times and see what happens.”

Intense preparation

Now, before a typical night game, Tracy will arrive in the Nationals clubhouse between 1 and 1:30 p.m. He eats lunch, and if he feels good he heads to the weight room. The most important part of Tracy’s routine comes next. He goes into the cage with hitting coach Rick Eckstein, an L-screen pulled to about 40 feet from the plate. First, he hits soft pitches — or “flips” — using only his left hand, called the “top hand drill.”

After 15 or so one-handed swings, Tracy begins his most serious work. Eckstein fires pitches at him — fastballs, sliders and curves — as hard as he can. The velocity mimics a 92- or 93-mph fastball, and Tracy treats the practice like in-game at-bats.

“I hit more when I’m not playing,” Tracy said. “When I was an everyday player, I’d take it easy.”

After the session with Eckstein, Tracy leafs through the book Nationals scouts prepare on the opposing pitching staff. Tracy places most of his focus on the opposing right-handed relievers, the pitchers he knows Johnson will try to match him up against. Tracy only wants to know the velocity of each of their pitches, and in what counts they tend to throw them.

Tracy goes through full batting practice with the rest of the Nationals, working up a sweat. Once the game starts, Tracy finds a spot in the dugout and watches the first four or five innings. At that point, he knows he may be called upon.

“You flip the switch,” Tracy said. “You’re cruising along, the game is cruising. That fourth or fifth comes along, you try to flip on, ‘Okay, here we go.’ ”

Tracy takes some more light batting practice and gets stretched by a trainer. Then the nightly mental grind begins. He constantly checks the pitch count of both starting pitchers – the opposition so he knows when a right-handed reliever could enter, the Nationals’ so he knows when he may pinch-hit for the starter, his most common deployment.

Tracy keeps in communication with pitching coach Steve McCatty and bench coach Randy Knorr. He wants to know exactly their thinking on how long the Nationals’ starter can pitch.

Crucial moments

His attention goes deeper than pitch counts. Tracy studies which opposing batters have had the most success off the Nationals’ starter, so he can be ready in case Johnson pulls the starter an inning early to avoid a difficult match-up. He checks and double-checks the lineup.

“You don’t want to take too many swings and tire, or you’ve taken them, and then something sneaks up on you and now you’re cold,” Tracy said. “You just never want that to happen. I just never want to get caught off guard. I’m almost overly cautious about being loose.”

Tracy thinks along with Johnson. By this point in the year, he can figure out when he will pinch hit before Johnson tells him. He knows he will be saved to hit with men on base, unless a solo home run can tie the game to take the lead. “He’s pretty close to the other managers I’ve had, excluding Lou Piniella,” Tracy said. “You never know what Lou was going to do.”

Tracy almost always hits in a crucial moment, against one of the other team’s best relievers. As an everyday player, Tracy almost never swung at the first pitch. As a pinch hitter, he hunts for a first pitch fastball, wary of falling behind in the count.

“These guys are one-inning guys,” Tracy said. “Their breaking balls are sharper. Their heaters are harder. They’re coming in trying to strike you out or embarrass you. If you get a first-pitch fastball you can hit hard, you’re not waiting around. You’d like to be able to see some pitches and get a little comfortable, but you can’t afford to do it.”

The approach has made Tracy one of the top bench players in the league. Tracy is batting .281 with an .837 on-base plus slugging as a pinch hitter this year; the league average is .237 and .673. Despite the 55 games he missed with a groin injury, Tracy is tied for third in the majors with 10 pinch-hit RBI.

The mental toll of pinch hitting wears down players. Tracy may go 0 for 3 and suddenly find himself hitless for a week. “When I get out, I think about my last at-bat until my next at-bat,” Tracy said. “I want the at-bat the next night. Even I don’t get a hit, at least I’m not thinking about that same at-bat.”

But it also has its rewards. Tracy frequently finds himself at-bat with the game on the line. In the moments when it all comes together, his first swing of the day leading to a walk-off hit or game-winning RBI, it makes the work worth it.

“You got a big knock,” Tracy said, “you go home and sleep a little better.”