Chicago ? Zach Day isn’t the NL rookie of the month for April, after all.

One day after the Montreal Expos right-hander was picked as the NL rookie for April, the honor was rescinded and given instead to Chicago Cubs first baseman Hee Seop Choi.

It turns out Day spent a few days too many in the majors last season to still be considered a rookie.

“I didn’t know that,” Choi said after the Cubs’ 6-4 loss to the Rockies on Saturday afternoon. “Wow.”

But Day wasn’t too bothered by the disappearing award.

“I’m not even thinking about it. It’s in the past,” he said in St. Louis, where the Expos lost 3-1 to the Cardinals. “I didn’t know about it until yesterday. Today it’s already gone. It’s not a big deal.”

Day was 2-1 with a 2.48 ERA in April. But he began the season with 81 days of major league service — including 52 days before Sept. 1.

According to rules established by the Baseball Writers Association of America, rookies cannot exceed 130 at-bats or 50 innings pitched, or have been on an active roster for more than 45 days before Sept. 1.

“Actually, coming into this year, I didn’t think I was a rookie,” Day said. “I felt like I had enough experience and I didn’t feel like a rookie.”

And he wasn’t. But Choi definitely is. Choi, the first Korean-born position player in history, didn’t make his major league debut until last Sept. 3.

“It’s just an award,” Day said. “I take my hat off to Choi. It’s a big accomplishment to get that award.”

Besides, it’s not as if he has to give back any goodies.

Each month, five media members covering each team are asked to pick the top player, pitcher and rookie in their league. The honorees were just announced Friday, so Day hadn’t gotten his commemorative trophy yet.

Choi will likely get his trophy in the next couple of weeks.

“I don’t even think about that,” Choi said. “I just want to play hard every game. I hit, play defense, I do everything hard because I want to win games.”

Choi hit .241 with five homers and 14 RBIs in April, and had a .552 slugging percentage. He hit safely in his first five games, and homered three consecutive days — April 15-17 against Cincinnati.

During his homer binge, he also reached base in 10 of 11 plate appearances.

“He’s doing well. He’s doing very well,” Cubs manager Dusty Baker said. “That’s a great honor. I’m hoping he gets the same honor at the end of the year.”

At least he won’t have any competition from Day.