David Ortiz is destroying all baseballs hurled towards home plate. While everybody in Boston is enjoying his hot start, nobody can honestly expect the free-swinging Ortiz to sustain this level of excellence. That’s just not realistic or possible. Or is it?

Ortiz is 37 years old, and six years removed from one of the most impressive four-year slugging stretches in baseball history.

From 2004 to 2007 he was unquestionably the best designated hitter in the world (an argument that’s still worth having today) and possibly the best overall player who stood left of home plate.

In 2005 Ortiz led baseball with 148 RBI, finished second in slugging percentage, third in OPS and runs, and fourth in on-base percentage. In 2006 Ortiz’s power numbers managed to get even better, as once again he led baseball in RBI (a statistic that’s value is lessening by the year), total bases, home runs and walks.

He qualified for the All-Star game for the third straight season and finished behind Justin Morneau and Derek Jeter for American League MVP (in 2005 only Alex Rodriguez received more votes for the award, and Ortiz most likely would’ve won it if he played in the field, even as the sport’s most incompetent first baseman).

He was a monstrous terror every couple innings; an increasingly difficult out in the same way beating someone at poker is increasingly difficult if he knows your cards. Ortiz guessed correctly on breaking balls that sat fat over the plate and knew when to lay off on everything he knew he couldn’t hit.

At the age of 31, his on-base percentage skyrocketed to a major league baseball leading .445 (with a .332 batting average) in 2007. Then he met natural decline, due to age and physical ailments—including an ongoing wrist injury that nearly ended his career.

Last year as the Red Sox were mired in an embarrassing charade of a baseball season, Ortiz’s brilliant play was very difficult to notice. In only 90 games he hit 23 home runs and saw his OPS go above 1.000 for the first time since 2007.

He made the All-Star team for the third straight season last year, but taking fan voting into account when judging one of the most gregarious figures in baseball history probably isn’t the most accurate assessment of how he’s playing.

Everything that’s been written so far you’re probably already well aware of. Now let’s look at the present day numbers to see if they can tell us anything about Ortiz’s immediate future.

Despite the smallest of sample sizes sure enough to turn around eventually (less than 75 plate appearances), Ortiz’s numbers are in another stratosphere right now. Despite a recent struggle that’s seen four hits in his last six games, he’s absolutely murdering the ball, with a .662 slugging percentage and a .353 batting average.

These numbers are obviously fantastic, especially for a 37-year-old athlete, but expect to see Ortiz’s stats fall back to Earth a bit in the weeks ahead because he isn’t walking. Like, at all. He has four walks in his first 73 plate appearances (his career walk percentage is more than double what it is right now), and the numbers indicate he’s either seeing the ball better than he was during his prime, or getting a little lucky.

(Quick tangent: Speculation that Ortiz’s boiling start is the result of steroid use is irresponsible amateurism. The idea was fueled by someone who isn’t looking at the numbers, but instead inanely trying to insert himself in a tired narrative that’s already fallen on deaf ears. Give it a rest. Back to my column.)

According to Fangraphs, Ortiz is swinging on 48.2% of the pitches he sees—a career high—and making contact with only 48.7% of ones he hacks at outside the strike zone (last season he was at an unconscious 77.4%, but his career average levels off at 55.4%).

Going from these numbers, it’s no surprise he’s failing to draw any walks at his typical rate; he’s letting loose at the plate in an uncharacteristic way. Time will tell how well he hits the ball throughout Fenway’s long summer nights, but so far we’re seeing a hitter whose a bit antsy in the box. Antsy is fine if you’re hitting the ball though.

The updated projections from Dan Szymborski’s ZiPS system (which uses weighted averages on four or three years of data, depending on the given player’s age) have Ortiz finishing with his best season since 2007. But keep in mind, the scintillating start intensifies nearly all the figures we’ve already talked about.

Ortiz is old for a baseball player, but still swinging for the fences with meaning. He’s amazing, looking like he could impact games for another five years. But when reality sets in, and it will, keep your expectations tempered. Ortiz is still an all-time incredible hitter, but if he keeps swinging the way he is, things could take a turn for the worse sooner than later.

Michael Pina is a writer for ESPN’s TrueHoop Network. His work has also been published on The Classical and ScoreBig. Follow him on Twitter @MichaelVPina.