With 13 games remaining in the 2021 regular season, the Houston Astros currently sit atop the American League West standings, six games ahead of the Oakland A's.

Their magic number to clinch the division is eight games, and baring some unforeseen circumstance that deviates them from this path, the Astros look to make the postseason for the 5th year in a row.

That being said, it's time to start asking questions about how this playoff roster will shape out when October rolls around.

1.) Who will be in the Astros' starting rotation?

A traditional playoff rotation usually consists of four starting pitchers. The answer may seem simple at first, but the final two spots may be up for grabs.

There is no doubt in my mind both Lance McCullers Jr. and Framber Valdez will be the number 1 and number 2 starters in this rotation respectively. McCullers is having a career year in wins, ERA and strikeouts. He has a 3-1 record with a 2.83 ERA over his last seven starts and has become the ace of this Astros' pitching staff. He is sure to start the first playoff game for Houston when the time comes.

Valdez started off the year red -hot and looked as if he could earn an All-Star nomination. He cooled off in June and July, but has bounced back again as of late. The 27-year-old has a 10-5 record with a 3.25 ERA and has consistently pitched five or more innings in every start since July 11th. He is a no-brainer to add to this playoff rotation as well.

That leaves two spots open among four potential candidates.

Had I been asked a month ago if Zack Greinke would make the playoff rotation, I would assume that question was intended to be satire.

For the majority of his career, Greinke has been nothing short of an ace, and has years of playoff experience as well. He started Game 7 of the 2019 World Series for the Astros (yes we all know how that went) and more recently was the winning pitcher for Game 4 of the 2020 ALCS against the Rays.

Over his last three starts, however, he has looked like a shell of himself. Greinke has given up a combined 18 runs over that span, and his ERA has ballooned from 3.66 to 4.11 this season.

Am I insinuating the 37-year-old will be left off the postseason roster? No chance.

But I am saying he will be the number 3 pitcher on this staff, which isn't a bad thing either.

Sure it's a far cry from being the ace of this rotation like everyone thought he would be coming into this season, but he can still be used efficiently in big games.

The former Cy Young Award winner will have two more starts before the postseason begins to improve his stats and gear up for another Astros playoff run.

The final spot in the rotation will be decided between Jake Odorizzi, Jose Urquidy, and Luis Garcia.

Odorizzi is still on the injured list with a foot injury, and therefore could be left off by default. Although he could be used as a long inning relief arm similar to Joe Musgrove and Brad Peacock's role in 2017 when he returns from the IL.

So that leaves Garcia and Urquidy and I think this spot will come down to health.

Garcia has been a mainstay in this rotation since he made his 2021 debut start on April 5th. In his first full major league season, Garcia is 11-7 with a 3.37 ERA. The 24-year-old started the season as a spot starter and filled in when needed, but pitched his way into becoming an everyday starter for this Astros' rotation.

Urquidy on the other hand has missed about two months of the season with right shoulder discomfort, but returned on September 3rd. He has made three starts and has only pitched past the 5th inning once since his IL stint. It is safe to say he is still trying to return to form as the season is coming to an end.

In my opinion, I would go with Luis Garcia to be the fourth starter on this playoff rotation due to the fact he is healthier and has been consistent this season on the mound.

Urquidy and Odorizzi can be used out of the bullpen if needed in addition to Cristian Javier for long relief appearances. There is one thing a team can never have too much of, and that's pitching depth.

2.) Hey Siri… Can Jose make the playoff roster?

Astros' outfielder Jose Siri has jumped onto the scene since being called up from AAA Sugar Land.

In 11 games, the 26-year-old outfielder has a slash line of .450/.500/.900 with three home runs and seven RBI.

As great as Siri has been, I don't think there is room on this roster for an additional outfielder this postseason.

The Astros already have Michael Brantley, Jake Meyers, Kyle Tucker as their starting outfielders with Chas McCormick filling in as the fourth man of this group. It would be hard to envision a scenario in which he could make a roster spot baring an injury of course.

Siri has shown he can be productive in the big leagues, but his time will come in 2022.

3.) What will the Astros' playoff roster ultimately look like?

Once the postseason gets started, teams must reduce their roster size back down to 26 players on their staff.

I'll get the easy ones out of the way.

Infield:

• Jose Altuve
• Carlos Correa
• Alex Bregman
• Yuli Gurriel
• Aledmys Diaz

Outfield:

• Michael Brantley*
• Jake Meyers
• Kyle Tucker
• Chas McCormick
• Yordan Alvarez

Catcher:

• Martin Maldonado
• Jason Castro

Pitcher

• Lance McCullers Jr.
• Framber Valdez
• Zack Greinke
• Luis Garcia
• Jose Urquidy
• Jake Odorizzi*
• Cristian Javier
• Ryne Stanek
• Ryan Pressly
• Kendall Graveman

*once they return from the injured list

These 22 players are sure to make the postseason roster barring any unforeseen circumstances.

The final four spots on the roster would go to bullpen arms, and maybe one more player to come off the bench.

Even though these two have been inconsistent at times this season, I would give Blake Tayler and Brooks Raley spots due to the fact they are left-handed pitchers and can be used in situations to get certain batters out.

For the final two spots, I would give one of them to Phil Maton over Yimi Garcia due to his stellar performance since being acquired at the trade deadline.

This may surprise some people, but I would give Marwin Gonzalez the final spot due to his postseason experience. He has been to the postseason three times with the Astros already, and would be a great locker room presence during this playoff run. Plus, it's always a good idea to have someone who can play multiple positions just in case, in addition to Aledmys Diaz.

There could be other surprises, but ultimately, I see this being the most likely 2021 MLB Postseason roster for the Houston Astros.