In an offseason when the Astros have to build a team that exceeds 2015's standard of contention, the position on the field we know the Astros absolutely must fill, as of now, isn't the one that will inspire ticket sales.

Of the Astros' six free agents - Scott Kazmir, Colby Rasmus, Chad Qualls, Tony Sipp, Oliver Perez and Joe Thatcher - the latter three are southpaw relievers.

Everybody, of course, needs a lefthander late in games.

Baseball's quiet period officially ends at 10:59 p.m. Friday, and free agents can then negotiate with any team.

"With the exception of lefthanded relievers, there's nothing I'd say we absolutely have to do," Astros general manager Jeff Luhnow said. "There's a lot we want to do."

There's the rub. The Astros have warm bodies - even viable options - everywhere outside of lefthanded relief, but upgrades at positions already occupied will be the biggest difference makers for Luhnow and Co. this winter, combined with the expected growth of some players retained.

Putting the bat on the ball more would be a good starting point.

"There are ways to improve as a team that don't involve external additions," manager A.J. Hinch said. "There's going to be natural growth and development from the guys we have. … I think our baserunning's going to improve. Obviously, making contact during the year can continue to improve. Some of that will be personnel changes; some of that will be continuing with the mindset and the development of what's going on with our current players."

A back-end flamethrower in the bullpen would be great, but a slam-the-door arm probably could come only by trade this winter. There are no free-agent relievers whom the Astros should be crawling out of their chairs to land, as they were last year (to no avail) when Andrew Miller was available.

There are good setup men out there, Sipp included, and he makes a ton of sense to bring back. Maybe the Orioles' Darren O'Day or the Royals' Ryan Madson or the Mets' Tyler Clippard becomes appealing. But resuming trade talks with the Padres for Craig Kimbrel or with the Reds for Aroldis Chapman might be the Astros' best avenue to ninth-inning assurance.

It's not that Luke Gregerson didn't do a good job. He may well be the closer again. What the Astros need is a chance to blow people away more often in relief, no matter the role - someone who can miss some bats with a 97 mph fastball now and then. (Vince Velasquez could be a dark horse to help here, but he'll be in spring training as a starter.)

Kazmir a tough call

A starting pitcher pick-up would be swell, too. The market's flush there, including Kazmir.

Maybe the Astros land someone above average for the rotation, or maybe it's someone who would be better categorized as "just another guy." But if Astros fans are looking for Johnny Cueto, Zack Greinke or David Price, look elsewhere unless the market reacts in a really funny way and prices drop.

There is no expectation the Jim Crane-owned Astros - who have never given a free agent a deal longer than three years - venture into the top tier and plop down for the nine-figure guys who might get contracts closer to 10 years.

"Our rotation is fine, but in every area, you have to look at is there an opportunity to upgrade here? And push everybody down a spot," Luhnow said. "It's highly unlikely we're going to get a No. 1 ahead of Dallas (Keuchel). It really is (thinking about) … are there some options to get guys behind or pair with Dallas to be a kind of 1-2 punch? That seems to be really important in the postseason and important to getting into the postseason.

"Or is it a guy that fits more of the back of the rotation, that gives us more depth and insurance if one of our guys has a hiccup?"

In the last year of a three-year contract, Scott Feldman is expected to return from a season-ending injury to his throwing shoulder by the start of spring training, but there's no way to say for sure.

With Keuchel, Collin McHugh, Lance McCullers Jr., Mike Fiers and Feldman - plus Velasquez and Dan Straily in the wings - the Astros do have arms. Signing another might stem spring competition. Spring competition, though, isn't what anyone's in this for. There's a guy named Mark Appel to watch, too.

Kazmir's tough end to the 2015 season might drive down his price, but he was still an excellent pitcher through July. What might depress Kazmir's price more than his performance is simply the market itself, with Jeff Samardzija, Yovani Gallardo and John Lackey among the other available arms out there beyond that first tier, and Kazmir blending into the group more than he would have had he finished with a flourish. Doug Fister, Mike Leake, Marco Estrada … the list that could sap his dollars goes on.

Kazmir's the local guy, so everything could conspire to make his return an easy one, but many teams will be in on him, and a three-year deal is probably needed.

Sipp likeliest to return

The 32-year-old Sipp, who lives in Houston and made clear he enjoyed his time here both verbally and with a 1.99 ERA, seems the likeliest of the Astros' free agents to return. He'll be among the least expensive options relative to other positions, simply because he's a reliever. But he'll still land an appropriate multiyear deal after two straight successful seasons and an ability to get both lefthanders and righthanders out.

The Astros liked Oliver Perez as a left-on-left reliever.

Arbitration taking hold

What the Astros do at two corner positions, left field and first base, and in arbitration can color the whole winter.

Do they want to re-sign the left fielder Rasmus, and do they need to prioritize him at a premium on a roster that includes outfielders Carlos Gomez, George Springer, Jake Marisnick and Preston Tucker? Are they willing to pay Chris Carter in arbitration after another year of frustrating at-bats with a power payoff that came just in the nick of time at the end of the season?

Arbitration eligibility is going to play a large role in how the Astros' winter proceeds. Between Evan Gattis and Keuchel, the Astros are looking at about $9 million in raises if long-term deals aren't worked out.

MLBTradeRumors.com projects Keuchel to make $6.4 million next season in arbitration. Luis Valbuena is to make $5.8 million, Carter $5.6 million, Jason Castro $4.6 million, Gattis $3.4 million, Marwin Gonzalez $1.9 million, Hank Conger $1.8 million, Josh Fields $800,000 and Sam Deduno $700,000.

Keuchel and Gattis both made roughly the major league minimum last season, a little more than half of a million dollars each. Now they could be worth about $10 million combined - and Keuchel may be in line for more money if he wins the American League Cy Young Award.

Of Valbuena and Carter, the former appears more likely to be tendered a contract through arbitration. The deadline for those decisions is Dec. 2.

"There's a lot of variables," Luhnow said of his payroll. "We've got a lot of arbitration players that we don't know where they're going to end up, and obviously, trades could change things right out of the gate. But we have resources to improve this team. That's not a constraint that I'm necessarily worried about right now. We just need to identify the opportunities and figure out a way to get deals done. But the resources will be there."