By MARK SIMON

Leading up to Opening Day, we’re going to preview all 30 MLB teams and how they could fare defensively in 2021.

Hitting and pitching are easy to evaluate when previewing a season. Defense is a little harder because of the nature of the numbers available to assess a player’s skill.

But that sort of thing is our specialty and we’re happy to take our best shot at it.

Today’s look is at the AL West.

Angels

Greatest strengths: Second Base, Third Base

Biggest Weakness: The Outfield

The Angels have had problems with run prevention lately which is problematic for a team hoping to contend in the AL West.

Let’s start with what’s good first. David Fletcher should land at second base full time this season and if he does play the whole year there, he could contend for a Fielding Bible Award. Fletcher has 13 career Runs Saved in the equivalent of a little more than a half-season there over the last three years.

Fletcher is there because José Iglesias is at shortstop, replacing Andrelton Simmons. Iglesias is up and down. He’s had three seasons saving at least 5 runs and two seasons costing his team 5 runs at shortstop. More of a sure thing is Anthony Rendon at third base, where he’s saved at least 9 runs three times, which makes you think his -1 last season was a small-sample aberration.

But the quality at these spots (and at catcher with Max Stassi) is hindered by the problems in the outfield. In the last two seasons, Justin Upton cost the Angels 17 runs in left field, Mike Trout cost them 13 runs in center field, and new acquisition Dexter Fowler cost the Cardinals 9 runs in right field.

Of those, Trout has the most upside, but he’s had five seasons with a negative Runs Saved in the eight years since his 21-Runs Saved season in 2012. Jo Adell could also provide a spark, though he cost the Angels 5 runs in right field last season too. Backup Juan Lagares has previously been a defensive star, but he can’t play all three spots at once.

Astros

Greatest strengths: Shortstop

Biggest Weakness: None

The Astros could be an excellent defensive team this season, particularly if the unknowns among their regulars, Myles Straw and Kyle Tucker, handle the outfield well.

Carlos Correa is now well established as a standout shortstop. He’s saved 37 runs the last five seasons, which ranks fifth among shortstops. First baseman Yuli Gurriel (9 Runs Saved the last two seasons and third baseman Alex Bregman (14 Runs Saved the last three) are standouts as well. José Altuve might be the weakest link, but he grades out about average the last five seasons by Defensive Runs Saved.

Tucker’s numbers in right are good (6 career Runs Saved), but keep in mind that it’s only 21 games and not enough sample to render a verdict. Straw comes out slightly above average in sum in a little more than 300 career innings in the outfield. Veteran Michael Brantley has a consistent history in left field.

Behind the plate, Martín Maldonado has a terrific reputation and the numbers, back that up (averaging 8 Runs Saved over the last five seasons). And on the mound, the Astros have one pitcher who is among the best fielders in recent memory in Zack Greinke.

If things go right, the Astros could be the best defensive team in the AL and challenge the Cardinals for best in baseball.

Athletics

Greatest strengths: Third Base, First Base, Center Field

Biggest Weakness: Middle infield

The Athletics have the best corner infield defense by far with Matt Chapman at third and Matt Olson at first. Neither put up big numbers last season (Chapman got hurt and played only 36 games) but there’s nothing to indicate any issues in their performance.

Center fielder Ramón Laureano could make a case for having the strongest outfield arm. In 2020, he eliminated a weakness from his game (handling deep fly balls) that resulted in his Defensive Runs Saved improving from -8 to 5. He could contend for a Fielding Bible Award if those improvements hold for 162 games.

Middle infield defense could be a weak spot for the Athletics though. Tony Kemp is expected to be their second baseman. He cost them six runs there last season, though he rated as average by Defensive Runs Saved in 55 games prior to that. New shortstop Elvis Andrus cost the Rangers 12 runs the last two years. His history indicates a mix of good and bad seasons with the latter coming more recently.

One edge the A’s have is a utility man with solid defensive value, Chad Pinder. Pinder’s value is greatest in the outfield (he has 14 career Runs Saved in left field and 7 in right) but he can also play any other position on the field save catcher and at least be adequate.

Mariners

Greatest strengths: First Base, Shortstop, Right Field

Biggest Weakness: Backup catcher

You don’t have to make a huge leap to believe that the Mariners are a very good defensive team. First baseman Evan White tied for the MLB lead by saving 7 runs with his defense last season. Shortstop J.P. Crawford ranked tied for third at the position with 6 Runs Saved.

Two defensive keys are making MLB returns. Mitch Haniger comes back to right field after missing all of 2020 due to injury. That’s where he saved 24 runs in the equivalent of about two full seasons of playing time from 2017 to 2019. Catcher Tom Murphy saved 7 runs as a part-time player in 2019.

And the concerns are not significant ones. Kyle Lewis graded out about average in center field last season but showed a flare for the spectacular play. Third baseman Kyle Seager’s numbers last season were a little below average and below his norm. But he’s rated as among the most reliable throwing arms in MLB and averaged 4 Runs Saved per season from 2017 to 2019.

The player who has the biggest defensive concerns is a backup, catcher Luis Torrens, who has cost his teams 15 runs in a little more than 500 career innings behind the plate. But if your biggest worry is a backup catcher, you’re probably doing alright. Other than that, we’ll see how Taylor Trammell and Jarred Kelenic fare in MLB. We don’t have enough minor league info on them to make a guess at how they’ll do.

Rangers

Greatest strengths: Right Field, Center Field, Shortstop

Biggest Weakness: Second Base

The Rangers have the potential for a very good defensive outfield. Joey Gallo saved an MLB-high 13 runs in right field last season with a good glove and a strong arm and the early returns on Leody Taveras (6 Runs Saved in 33 games) were positive.

But this is a team that is a puzzle in the infield. Ronald Guzmán regularly rates average at first base. He’s the only one on the infield for whom there aren’t questions. At second base, Nick Solak has cost the Rangers five runs in just under 200 innings, but he’s going to be given a chance there. Their usual second baseman, Rougned Odor, is expected to shift to third base, where he’s never played in his pro career.

That leaves now-shortstop Isiah Kiner-Falefa. Kiner-Falefa had a breakthrough at the plate last season, as his bat caught up to his excellent glove at third base. He’s saved 17 runs in three seasons at the hot corner for the Rangers, a good enough showing that Texas thinks he can replace Elvis Andrus at shortstop. Kiner-Falefa does have 4 Runs Saved in 17 career games at shortstop, so assessing him as a standout there doesn’t seem like a reach.