Updated

The Seattle Mariners announced Tuesday that they are moving in portions of the outfield wall at Safeco Field for the 2013 season.

The biggest change will come in the left-center field alley, where the distance will decrease from 390 feet to 378 feet.

Another noticeable change will be in the left-field corner, where the hand- operated scoreboard will be relocated to a new location above left field as part of seating modifications that will be announced at a later date.

"Our goal was to create an environment that is fair for both hitters and pitchers. Considering the current field dimensions as well as the climate in and around Safeco Field, we feel this will be accomplished with this new layout," Mariners general manager Jack Zduriencik said.

The changes are the first to the field dimensions since the ballpark opened in 1999.