HOUSTON -- This offseason figures to be the most important of general manager Jeff Luhnow's tenure, as he enters his sixth season with the Astros in 2017. The team took a step back after 2015's surprising run to the postseason, with major question marks at first base, catcher, outfield and in the rotation.
The Astros figure to have the payroll flexibility to be active in the free-agent market, but the pool of talent isn't deep. That means clubs might have to overpay for what they want. Houston will likely be in the market for a starting pitcher, unless it decides to beef up on offense and roll the dice with the same arms it had this season.
The team's Minor League system has seen most of its top prospects hit Houston in recent years, led by infielder Alex Bregman and pitchers Joe Musgrove, Jandel Gustave and David Paulino in 2016. Most of the organization's top Minor League prospects are at the lower levels, which makes external additions this offseason more likely.
• Astros reach brink of playoffs after rough start
Despite this season's early end, the Astros figure to remain a contender in 2017. They have a talented young lineup and a bullpen that, if it returns intact, could be among the best in the game. Whatever the Astros decide to do with the starting rotation could hold the key to their fortunes.
Arbitration-eligible: SP Dallas Keuchel, IF Marwin Gonzalez, SP Collin McHugh, RP Will Harris, SP Mike Fiers, RF George Springer, C/DH Evan Gattis (team has $5.2 million option which, if not exercised, would make him arbitration-eligible).
Free agents: C Jason Castro, OF Colby Rasmus, SP Doug Fister, 3B Luis Valbuena, RP Pat Neshek ($500,000 buyout on $6.5 million option for 2017).
Rotation: The Astros didn't get near the same kind of production they got from their rotation in 2015, which presents a dilemma. Do they stick with Keuchel and McHugh at the top of the rotation and hope they return to 2014-15 form, while hoping Lance McCullers Jr. can remain healthy? Or do they make an offseason addition to bolster the top end? The free-agent market isn't a good one, and a trade would be costly. Fister's rough September probably means he's not coming back, while a decision will need to be made about whether or not to tender Fiers. Musgrove pitched well overall in his debut -- and other young arms like Paulino, Brady Rodgers and Francis Martes could push for some starts, as well.

Bullpen: Although the Astros squandered more than their share of leads in the late innings, the bullpen did a solid job overall, especially considering how undermanned the rotation was down the stretch. The closer's job in 2016 went from Luke Gregerson to Harris to Ken Giles -- the team's biggest offseason acquisition prior to the season, who performed to mixed results. Most of the key arms will return, including Gregerson, Harris and Giles, at the back end. Rookie Chris Devenski emerged as a force in the bullpen, with his ability to pitch in multiple innings, and manager A.J. Hinch made it clear he preferred him in that role over starting. Neshek wiped out right-handed hitters, but he has a costly option that might not get picked up. Lefty Tony Sipp had a campaign to forget in the first season of his three-year, $18 million deal, but he'll return.

Catcher/DH: Castro is a free agent for the first time, and the Astros have a big decision to make. They can try to re-sign him -- and likely overpay -- after a third consecutive lackluster offensive season. Or, they could try to acquire another catcher. Again, the free-agent market is top heavy (Wilson Ramos, Matt Wieters), but the Astros don't have catching depth at the upper level of the Minor Leagues. Gattis started roughly one-third of his games at catcher when he wasn't the designated hitter and had success throwing out runners. But the team doesn't believe he's built to be an everyday starter behind the plate. Max Stassi has gotten playing time at the end of the last few seasons, but he isn't a prospect. Maybe Houston could try to pluck Brian McCann away from the Yankees in a trade?
First base: The Astros let Chris Carter walk following the 2015 season (and watched him knock a National League-high 41 homers for the Brewers), as they struggled to find consistency at the position. Prospect A.J. Reed couldn't hit in his Major League debut and will need to get in better shape to push for the job. He was part of a revolving door at first that included rookie Tyler White, Yulieski Gurriel and Gonzalez, who was the most consistent performer of the group. But Gonzalez's value is as a utility player who can move all over. Gurriel could get much of the playing time going forward if Reed doesn't develop or the Astros don't add a first baseman in the offseason.

Second base:José Altuve separated himself as one of the top hitters in the game by winning his second American League batting title in three years, in addition to reaching career highs in homers and RBIs. Altuve remains a huge bargain for the Astros. He'll make $4.5 million next season and then has team options for 2018 ($6 million) and '19 ($6.5 million). Altuve switched to agent Scott Boras during the season in anticipation of his next deal, which should be a whopper.

Shortstop: Former No. 1 overall pick Carlos Correa followed up his AL Rookie of the Year campaign in 2015 with a solid, though not spectacular, season. He became an RBI machine in the cleanup spot as the season wore on and recorded five walk-off hits. He played nearly all of 2016 at 21 years old and remains under club control for four more years. The Astros will probably explore a long-term contract at some point, but Correa will be entrenched at shortstop for at least the next few seasons.

Third base: Valbuena is unlikely to be back because the Astros have options at the hot corner. Bregman played very well at third after he was called up in July and figures to enter the season as the starter. Gurriel, a third baseman by trade who played the position well when Bregman was out for two weeks late in the season with a hamstring injury, figures to be in the mix, as well. Either way, the Astros have good long-term solutions at the position.

Outfield: The Astros will have two new starting outfielders on Opening Day 2017, after beginning '16 with the trio of Rasmus, Carlos Gómez and Springer. Rasmus, who took a $15.8 million qualifying offer for '16, won't return after a woeful season that ended in injury, and Gomez was dumped in August after a down year in an Astros uniform. Defensive specialist Jake Marisnick and rookie Teoscar Hernández saw time in the second half, but the Astros need upgrades. They could especially use a left-handed-hitting outfielder with power. Josh Reddick, anyone? Springer provided power and speed at the top of the order, though he still struck out quite a bit. Springer, though, could be moved to center if Houston acquires a right fielder. Minor League outfielder Derek Fisher could also be in the mix.