Jim Johnson, an Oriole off and on since 2006, had 21 career saves prior to his 26 in the first half of 2012. (Jonathan Daniel/Getty Images)

With a few pieces of tape, Jim Johnson attached a pocket schedule to the side of his cherry-wood locker inside the Baltimore Orioles clubhouse.

After each game, the Baltimore closer scribbles an “X” over the date with a black marker. The schedule is a bit worn, as the month of April has already fallen off. It isn’t a track of his daily progress; instead, it’s a way for him to stay afloat.

“Trust me, there’s days I honestly don’t even know what day of the week it is,” he said.

It would have been easy for Johnson to feel a bit overwhelmed this season. But he hasn’t.

Johnson, 29, entered the season for the first time in his six-year career as the team’s full-time closer. He’s on track for a career-high number of appearances and will come close to his high mark of innings. Before becoming the team’s closer, Johnson worked in relative anonymity as a setup man and middle reliever.

But he’s been quite comfortable in his new, pressure-filled role. Last week, he pitched in his first all-star game and he led the major leagues with 26 saves during the season’s first half. Saturday night’s blown save was just his second of the year.

“I’ve always been more of a team-oriented guy, so people see the stats and the saves and whatnot,” Johnson said. “But I like to say that I’ve had a big part in where we are in the standings. That’s the most important part.”

The Orioles (46-42) are vying for their first playoff appearance since 1997, and they just began a stretch of 20 straight games without a day off. It’ll be a good chance to see how the team responds, as all but four of those games are against teams with winning records.

Johnson’s success this season may be staked on the development of his two-seam fastball. He’s thrown the pitch three times as often as he did last season, as he’s relied far less on his regular fastball.

The pitch moves with the same 94-mph speed as his fastball, but it sinks as it crosses home plate. Johnson has used the two-seamer, along with his effective change-up, to force batters into groundouts.

The majority of his outs come from play, as he has just 23 strikeouts. That ranks him tied for last among major league pitchers with at least 19 saves. But his 0.83 WHIP is third among those same 13 pitchers.

Baltimore Manager Buck Showalter first saw Johnson pitch a few years ago during a rehab assignment in Bowie. Johnson worked two quick outs, but then decided to work on his change-up. The result: a long home run.

“He said, ‘Did you like [my change-up],’ ” Showalter recalled. “I said, ‘I hope you’re working on it.’ ”

Showalter called Johnson a “horse” and said that he has the most difficult job on the team. Johnson has pitched 381 / 3 innings this season and appeared in 38 games. His ERA is at a career-low 1.41, which is third among pitchers with 15 or more saves.

In the month of June, Johnson appeared in 13 games and allowed just three earned runs and five hits. He allowed no hits as he picked up a pair of saves against the Nationals.

When Johnson entered last week’s All-Star Game in Kansas City, he was joined by some familiar company. His catcher, Matt Wieters, was behind the plate and Orioles outfielder Adam Jones manned center field. Johnson worked a quick eighth inning, needing just 11 pitches to retire three straight batters.

“The groundwork that we laid down in the first half, we just have to keep the course,” said Johnson. “. . . We have to play to our potential, not try to overdo it and do what we know.”