LONDON, July 1 (Xinhua) -- Fifth seed Kei Nishikori of Japan has pulled out of the Wimbledon Championships because of a left calf injury, organizers said here on Wednesday.

The decision was announced before his second round match against Colombian Santiago Giraldo in the second match on Centre Court.

The same injury had forced him to withdraw midway through his semifinal against Andreas Seppi in Halle, a warm-up tournament for Wimbledon.

World No. 60 Giraldo thus became the first man through to the third round of the men's singles.

Nishikori, 25, said the injury worsened during his five-set win over Simone Bolelli in the first round.

"It got better before the first match, you know, last week," Nishikori said. "I thought it was really going to be okay. But last match in fifth set I was hurting too much.

"I don't know how I fought through but somehow I won. I thought it would get better in two days but today it was still hurting, just walking and running, so I decided not to play. It is not a big injury, I think a little tear.

"I'm very disappointed. Especially it's a Grand Slam. I thought I was playing well on grass. So very unfortunate to lose this chance. But, you know, I try to keep it up. Hopefully I can do well in the US series."

"I have one month before Washington. So I'm sure it's going to be okay."