Seattle Mariners third baseman Ben Williamson makes a throw to first base during a game against the Athletics on May 6 at Sutter Health Park. Neville E. Guard-Imagn Images

Seattle Mariners Third Baseman Draws Rave Reviews From Coaches For His Defense

Originally posted on Seattle Mariners on SI
By Teren Kowatsch | Last updated Jul 20, 2025 4:00 PM ET

SEATTLE — The Seattle Mariners' defense at third base has been some of the best in the majors this season, mostly due to rookie infielder Ben Williamson.

The 2023 second-round draft pick was brought up to the big leagues on April 13, and has manned the hot corner for the Mariners since. His coaches have taken notice of his defensive contributions.

Seattle bench coach Manny Acta had high praise for the rookie third baseman in a post on "X" on Saturday:

"Ben Williamson is the best defensive 3B in the (American League). Yes, I said it.

Ben Williamson is the best defensive 3b in the AL. Yes, I said it.
— Manny Acta (@MannyActa14) July 19, 2025

Acta's assessment isn't inaccurate.

Williamson is first among AL third basemen in defensive runs saved (DRS) this season with eight. The second-highest AL third baseman, the Toronto Blue Jays' Ernie Clement, has six. He has one out above average, which ranks in the 77th percentile in baseball, per Baseball Savant. He has a 76% success rate on plays, which is tied for third in the majors. He has a .982 fielding percentage this season and has committed just three errors in 169 total chances across 616.1 innings and has helped turn eight double plays.

"It's been impressive," Mariners manager Dan Wilson said before a game against the Houston Astros on Sunday. "I think as young players, when you get to the big leagues you don't know what to expect. And when you look at what (Cole Young) and Ben have done defensively, especially in Ben's case, it's been really solid. We kind of joked yesterday — Benny dove for the ball down the left field line there and I think that's the first ball I've seen him miss on a dive since he's been here. He's just been so good and it seems like anytime the ball goes down there, it's an out."