National League home run race reminiscent of 1998's

The 2015 major league baseball season has had many defining moments and trends, but the most interesting of them all could turn out to be the National League home run race.

Three NL players – Giancarlo Stanton, Bryce Harper and Todd Frazier - are involved in a chase that is reminiscent of the 1998 competition among Mark McGwire, Sammy Sosa and Ken Griffey, Jr. Through June 22 of that season, the top three contenders in the chase had 28 or more home runs.

The Los Angeles Angels’ Albert Pujols has 23 home runs (on pace for 52). If he and the NL leaders continue their home run-hitting pace, it would be the first time that three or more players hit 50 home runs in a season since 2001, when Sosa, Alex Rodriguez, Luis Gonzalez and Barry Bonds did so. That season was the only other year besides 1998 in which three players hit 50 or more home runs.

The contenders

Stanton: 25 home runs, 70 games, 265 at-bats

Why he might win: Stanton has four of the 10 longest home runs this season, as calculated by ESPN’s Home Run Tracker. Stanton also has the advantage of having the most home runs in baseball (25), including 10 since the start of June.

Why he might not: Stanton has not been good at getting to pitches on the outer half this season. Eight of his 25 home runs (32 percent) have come against pitches on the outer half or further away (compared with 44 percent for the league average). And he has missed on 45 percent of his swings against pitches on the outer half, most in the major leagues among qualified hitters.

Harper: 24 home runs, 67 games, 226 at-bats

Why he might win: Harper is hitting a home run every 9.4 at-bats, best in the majors among qualified hitters. Harper has distributed his home runs fairly evenly. He has eight home runs to right, nine to center and seven to left.

Why he might not: In terms of the home run chase, Harper’s patience could turn out to be a flaw. He has walked in 19 percent of his plate appearances, most in baseball among qualified hitters. Harper has also been vulnerable on the inside corner, with one home run in at-bats ending with a pitch on the inner-third of the strike zone. If Harper doesn’t get enough at-bats or pitchers start coming inside more often, he could fall off pace.

Frazier: 23 home runs, 67 games, 264 at-bats

Why he might win: Frazier is crushing everything thrown on the inner half of the plate and has 13 home runs on pitches thrown in that location. Ten of his home runs have come on the outer half, and his plate coverage makes it more difficult for pitchers to adjust and easier for Frazier to hit home runs.

Why he might not: Frazier’s 23 home runs are six behind his career high, which he reached last year. Before that season, Frazier hit 19 home runs in consecutive years. Frazier, 29, has never hit more than 30 home runs in a season but is on pace for 55 this year.

This season’s home run chase probably won’t end up with as many home runs as 1998’s did, but the competition is strong nonetheless.

Assuming the three players stay on their current pace, the final results would have Stanton winning the race … narrowly.