The two major pre-season candidates to win the American League Rookie of the Year award have certainly not disappointed a month and a half into the 2014 season. Then again, Jose Abreu and Masahiro Tanaka are not your typical rookies. Abreu is a 10-year veteran of professional baseball in Cuba, where he set a single-season home run record and won an MVP in 2008. Meanwhile, Tanaka has seven years of professional experience pitching in Japan, where he most recently finished 2013 with a 1.27 ERA and perfect 24-0 record.

Since the beginning of the year, my son and recent college graduate, Jason (Congratulations, Jason!), has been speculating whether Tanaka can have a perfect record in Major League Baseball like he did last year in Japan. I've been telling him it’s never been done before and is pretty much impossible. The best perfect record in MLB was 12-0 by Tom Zachary with the Yankees way back in 1929, but that was in only 120 innings. An ERA qualifier has never had a perfect record, but we're now a quarter of the way through the season, and Tanaka is a perfect 6-0. Can he do it? Still extremely unlikely.

Before we crown Tanaka, we must consider the case of Abreu, who is off to a sizzling start and has already been well recognized for his accomplishments with some awards in his short time in MLB. In April, Abreu set all-time rookie records with 10 home runs and 32 runs batted in en route to dual AL Player and AL Rookie of the Month honors. His current total of 15 home runs leads all of baseball by three and his 41 RBI lead all AL players by six.

Of course, win-loss record, home runs, and RBI do not accurately measure the total value of a player, so even though those narratives might drive the ROY selection of some voters, let’s look at some statistics that better compare the two players.

Since Abreu is a hitter and Tanaka is a pitcher, their on base plus slugging (OPS) and OPS Allowed numbers are not directly comparable. Obviously, Abreu wants his to be higher and Tanaka wants his to be lower. However, when measured as a rank in the AL, Abreu is fourth-best among hitters and Tanaka is sixth-best among pitchers, so the two are very close.

Win Shares, a comprehensive measure of value created by Bill James that allocates a team’s actual wins to individual players based on their contributions, and Wins Above Replacement (WAR) are probably the best stats we have to directly compare the two. They are meaningful for Abreu, especially, since OPS only accounts for his offensive contributions. And Abreu has actually cost the White Sox three runs with his defense (per Defensive Runs Saved) and a run with his baserunning (per Baserunning Runs).

Even with those negatives, Abreu and Tanaka remain neck and neck, with the former leading in Win Shares and the latter in WAR. For now, this race is too close to call.