Welcome back to The Rotation! Here's a look at five topics worth talking about this week in MLB.

1. West depth?

The basic gist of the National League West this decade is that the Dodgers win division titles, the Giants win World Series titles and everybody else is just sort of scenery.

Going into the '17 season, there were some underrated reasons to be optimistic that the division would run deeper than those two long-time rivals, and, in the very small sample that is one week of action, those reasons have been brought to life.

Obviously, whether the D-backs (6-1) and Rockies (5-2) can legitimately build on their encouraging starts remains to be seen. But the early outcomes are important for these clubs. It's no secret that a new, Mike Hazen-led regime in Arizona could look to blow things up this summer if 2017 plays out similarly to 2016, and the Rox had emotional incentive to not let an injury-riddled spring camp overtake what had appeared to be organizational momentum.

Last year, it was Arizona bit hard by the spring injury bug when A.J. Pollock broke his elbow in the final weekend of exhibitions. This year, a healthy Pollock's first-week slash of .333/.360/.583 atop the order has keyed an explosive offense. Arizona's averaging 6.9 runs per game and has been especially productive in the mid-to-late innings.

You expect the Rox to score runs, but the early positives are largely a product of 'pen improvement. Colorado invested in Mike Dunn and Greg Holland this winter, and those two guys have been basically flawless (no hits, one walk and six K's for Holland; one hit, two walks and seven K's for Dunn) in their first four innings apiece.

With new blood in the dugout (Torey Lovullo in Arizona, Bud Black in Colorado), there was new hope of a rise in respectability. The West remains the Dodgers' to lose, and it's way too soon to know if the Giants' continued bullpen blowups are an early blip of a systemic extension of '16 that will ultimately undermine them (for whatever it's worth, the last Giants team to start out 1-5 was the 2008 club that finished with 90 losses).

All we know for now is it would be fun to see the NL West evolve into something other than the typical two-team race.

2. Clock and spiel

Among the rule changes in MLB this season is a 30-second time limit for managers to decide if they want to use a replay challenge, which sounds pretty straightforward.

But already, there has been some confusion about how that process works.

"It's not quite the way we expected," Indians manager Terry Francona told reporters last week. "I thought there was going to be a clock, and they don't have the clock going. Right now, it's at the umpire's discretion. … I just think it might be set up to maybe have a controversy you don't need."

There is, in fact, a clock (it's the same one that counts down the 30 seconds available to coaches for mound visits), but, as explained by Red Sox skipper John Farrell, that clock doesn't begin until the manager signals to the umpire that his club wants to take a look at the replay to decide whether to challenge.

"We have probably an eight-to-10-second buffer for when we're going to the top step of the dugout," Farrell said. "Once I signal to the umpire that we're taking a look, that 30-second clock begins."

So you have roughly 10 seconds to decide if you want to use your 30 seconds? Francona might be onto something here. Because anything at the ump's discretion is subject to potential differentiation from night to night.

3. Yadi, Yadi, Yadi

The three-year extension that will basically ensure Yadier Molina is a Cardinal for life set off a lot of discussion about Yadi's future Hall of Fame chances. Molina's Cooperstown case is a complicated and likely controversial one, because it's based more off of stature than stats. Molina has a career OPS+ of 98, or 2 percent below league average. His career Wins Above Replacement mark, entering this week, is 33.6 -- exactly the same as that of Buster Posey, a player almost five years younger than him.

And yet, there's no denying Molina has been one of the most respected and accomplished catchers of his time. Teammates swear by his impact and influence on the pitching staffs that were the backbone of nine postseason appearances and two World Series titles, and Molina's mere presence behind the plate compelled opponents to limit their stolen-base attempts against him.

A rival player once remarked that Yadi is like a "unicorn" -- a legend undefinable in concrete equations. (The player was using the term derisively, though I suppose it can go either way.)

So I ran the Yadi conversation by pending Hall of Famer Ivan Rodriguez -- one of only two catchers (Johnny Bench is the other) to get elected on the first ballot and one of only four catchers (Mike Piazza, Gary Carter and Carlton Fisk are the others) voted in by the Baseball Writers' Association of America this century.

As you might suspect, Puerto Rican catchers have each other's back.

"Yadi deserves [the Hall]," Pudge said. "He has proved to everybody that he's the best catcher in the game, absolutely. He's still got a few years left. I think he's probably going to put up some more numbers in the next three to four years and, after that, he can be a Hall of Famer."

4. Sticky situation

Speaking of Yadi, there were some hilarious proclamations of innocent ignorance associated with that ball that stuck to his chest protector last week, with manager Mike Matheny saying he didn't know "what in the world really happened there" and words like "somehow" and "inexplicably" used in reporters' copy.

Hey, we're all adults here. It was pretty obvious that there was something sticky applied to the ball, the chest protector or both, which is why you can't blame a reporter for asking Yadi about it after the fact. Nor can you blame Molina for saying it was a "dumb" question, because, really, he'd be dumb to admit to even minor flaunting of the foreign substance rule.

We say this anytime there is a prominent instance in which substances get scrutinized (most notably three years ago this month, when Michael Pineda got a 10-game suspension as a pine tar penalty), but it would be nice if Rule 3.01 could be updated to acknowledge the very basic fact that it is being violated in literally every Major League game (unless, of course, there really is a valid dermatological reason to have sunscreen in domed stadiums).

Create a list of approved substances and have players reveal what they want to use and where and how much they want to use it to the umpire so that we don't have these occasional situations in which players like Pineda and Molina are made to look like cheaters for doing something that is, in fact, a common practice.

5. Serg up the standings?

In his 37th year of life, in his 19th trip to the Masters, in his 71st major championship start Sunday, Sergio Garcia finally won the big one. You had to be a total curmudgeon (or related to Justin Rose) to not feel genuinely happy for him.

The clearest MLB comparable to Serg is easily identified: It's Felix Hernandez. He's the longtime ace of the franchise with MLB's longest active postseason drought (dating back to 2001) and the undisputed possessor of the title "Best Active Player to Never Reach the Postseason." None of King Felix's 2,426 2/3 career innings -- innings in which he's accrued three top-two finishes in the Cy Young voting (with one win) and an ERA+ 26 percent better than league average -- have occurred in October. A waste if ever there was one. 

Can Felix and the M's make Garcia-like gains this season?

Well, let's put it this way: They've double-bogeyed the first hole.

The Mariners are an MLB-worst 1-6. They are hitting a brutal 8-for-57 (.140) with runners in scoring position, with a .178 average overall. They coughed up a 9-3 lead against the Angels in the ninth inning on Sunday and lost, 10-9. And Felix himself left his Opening Day assignment with a minor groin injury and has a 1.36 WHIP through two outings.

So it's not looking good in Seattle entering Monday's home opener against the Astros. But if the Mariners can somehow shake off that brutal road trip and get to October, Felix would look pretty good in a (Northwest) Green Jacket.

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Anthony Castrovince is a Sports on Earth contributor, MLB.com columnist and MLB Network contributor. Follow him on Twitter @Castrovince.