Braves shortstop Andrelton Simmons ranks at or near the top of most defensive rankings again this season, using standard or advanced metric stats, and a third consecutive National League Gold Glove seems a good bet.

But it might not be the absolute lock that most of us have thought it would be for this year and the next decade or so.

That’s because Giants shortstop Brandon Crawford is also superb with the glove, plays for one of the sport’s current marquee teams, and produces a lot more offense than Simmons. Although offense is not supposed to be factored into the equation, many voters have long let it influence their decisions.

Crawford, who made his first All-Star team this season, was batting .270 with 19 homers, 75 RBIs and an .824 OPS before Friday, while Simmons had a .259 average with three homers, 32 RBIs and a .657 OPS.

You’d be hard-pressed to find anyone in baseball who believes Crawford is better or even as good defensively as Simmons, widely regarded as the best defensive shortstop of his generation. Some consider Simmons the top defensive player in baseball regardless of position. (Simmons won the NL Platinum Glove Award in 2013 as the best defensive player in the league, while Cardinals catcher Yadier Molina won the award in the other three of the past four seasons).

Still, Simmons and Crawford were dead even this season in some of the more sophisticated defensive statistics, including Defensive Runs Saved, where each had 19 before Friday. They trailed Rays center fielder Kevin Kiermaier, having a phenomenal year in the field with 30 DRS before Friday. No other player in the majors had more than 16.

In the Braves’ game against the Cubs Friday, Simmons made a fielding error when he booted a grounder with two out in the seventh inning, his first error since June 15.

Another metric stat, Defensive WAR (Wins Above Replacement), also had Simmons and Crawford tied for second in the majors regardless of position with a score of 2.7, again trailing only Kiermaier (3.6).

Simmons leads the majors in range-factor statistics, and also was the leader in conventional defensive stats including fielding percentage among shortstops (.994) and double plays turned (88) before Friday. His error led to an unearned run in the seventh inning Friday, and was his first error since June 15 at Boston.