We tend to parse words to an extreme degree in baseball. Does “most valuable” really mean “best?” [Side note: Nearly all of the time, yes, it does]. “Control” isn’t exactly the same as “command.” Are an “ace” and a “No. 1” starter the same thing? Depends who you ask.

So today’s topic in MLB.com’s weekly division notebooks may mean different things to different people. The question is: Who is each team’s most indispensable player? Which is the player who, if you removed him, the club would miss the most?

It may be because there’s just not a viable backup. It may be because the player fills a role that affects the team in numerous ways. It also might be as simple as, he’s really that good. Here are the choices for the National League West.

D-backs, SP Zack Greinke

It may seem a bit contradictory, but as the requirements of starting pitchers have diminished, the value of truly elite starters may be greater than ever. It’s a lot easier to piece together 160 outs or so in a week if you’ve got one guy who can routinely get 20 or more of those outs at a time.

Following his seven innings on Wednesday, Zack Greinke is on pace for 235 innings. That makes aggressive bullpen usage a whole lot easier. Oh, and he’s been brilliant in those innings as well, with nearly an 8:1 strikeout-to-walk ratio, a 2.78 ERA and nine straight quality starts.

Greinke exited Wednesday’s game with abdominal tightness, so the hope is that he’s not out for long. It would create a huge hole for the surprising D-backs if he had to miss significant time.

Dodgers, 3B Justin Turner

Here’s a team with a lot of viable options. Clayton Kershaw. Kenley Jansen. Cody Bellinger. But the guy who always seems to make them go is Justin Turner.

That’s partly just because Turner is really good. He hits for power, is an on-base threat and plays a solid third base. (Though he’s no longer the multi-position defender he once was.) But more specifically, it’s in large part due to which side of the plate he bats from.

The Dodgers are heavily left-handed, as Bellinger, Joc Pederson, Alex Verdugo, Max Muncy and Corey Seager all hit from the left side. With A.J. Pollock out and Chris Taylor struggling, Turner provides essential lineup balance.

Giants, SP Madison Bumgarner

San Francisco has four relievers who have 19 or more innings, and collectively they’re probably the greatest key to what success the Giants have had, playing more or less .500 ball over the past few weeks. But for those relievers to stay fresh at all, somebody must get a few innings at the start sometimes, which makes the answer Madison Bumgarner.

Yes, Bumgarner has been inconsistent this year, with a 4.04 ERA. He also has 14 2/3 more innings than any other Giants starter. On a team starved for quality starting pitching, Bumgarner’s effectiveness and durability are essential. If they deal him before the Trade Deadline, he will be deeply missed, not only by fans but by manager Bruce Bochy and his coaching staff.

Padres, IF Manny Machado

Here’s a case where there’s no reason to get cute. Chris Paddack has had a great year, and the Padres have missed Fernando Tatis Jr. But it’s Tatis’ absence that has magnified why the choice is Manny Machado.

The superstar slugger started the year playing a brilliant third base. He didn’t get off to a roaring start at the plate, but he was contributing. When Tatis went on the injured list, Machado slid right over to shortstop without a hiccup. The bat has come on since then, too.

The Padres would rather not have to play Machado at short. They'd like to have Tatis in the lineup, and Machado is a better defender at third. But goodness, that’s about as good an insurance policy as you’re going to find. And he can hit a bit to boot -- just ask Kershaw.

Rockies, 3B Nolan Arenado

There’s a better case than you might think for Trevor Story, whose excellent defense at shortstop and strong baserunning make the gap at the top pretty narrow. Story is an excellent player, and it would probably be harder for the Rockies to find an adequate fill-in for him than even for the choice here.

But, come on, Nolan Arenado is that good. He hits for average and power. He controls the strike zone. And he is, of course, an absolutely dazzling third baseman. He’s also unquestionably the face of the franchise, for those of you who are into such things.

The gap is closer than conventional wisdom might have you believe. But it’s still real. Arenado is the Rockies’ most indispensable player.