Without Andrew Luck, a lost season for Colts and plenty of work ahead

The Indianapolis Colts ended the season with a 22-13 victory over the Houston Texans on Sunday. Here's a recap of their 4-12 season and what's next:

Season grade: Below average. The season was going to be a challenge for the Colts without quarterback Andrew Luck, but their inability to close games and coach Chuck Pagano's struggle to make halftime adjustments ended up being a common theme throughout the year. Indianapolis was 2-7 when it had a lead at halftime. Closing out games has been one of Luck's strengths.

Season in review: Injuries. Poor second-half play. And more injuries. Highlighted (or lowlighted) by Luck's shoulder injury, the Colts put 18 players on injured reserve this season. Pagano said he's never been part of anything like that in his 33 years of coaching. That was only a portion of the problems for the Colts, who missed the playoffs for the third straight season. General manager Chris Ballard knew his first season would be a challenge, but a season without Luck showed how flawed the roster remains. Ballard cleaned house by releasing or not re-signing several key older players on the roster. He replaced them by signing younger players to shorter contracts to evaluate whether they fit in with the organization for the long haul. The emphasis going forward for Ballard will be to build the roster through the draft, because he doesn't believe in cutting corners by signing overpriced free agents.

Biggest play of the season: Quarterback Scott Tolzien's second pick-six in Week 1 opened the door for Jacoby Brissett, who was acquired from New England a week earlier, to be the starting quarterback the rest of the season. Brissett, despite some rough patches due to not having an offseason to learn the offense, gave the Colts a better chance to win on a weekly basis than Tolzien. Brissett has trade value and offers insurance for the Colts if Luck is not ready for next season.

He said it: "We had a heck of a run for three years, and two 8-8s and now we're sitting where we're sitting. It's unacceptable, and every guy in that locker room will tell you that. We don't come to work to lose. We don't do that. It's unacceptable." -- Pagano on the franchise's first losing season since 2011.

Key offseason questions

Coaching uncertainty: Of all the offseason issues the Colts will be dealing with, no two are more important than Luck’s health and who will be coaching the team in 2018. All indications are that Chuck Pagano will not return next season. The organization can’t risk wasting any more of Luck’s years by rolling the dice on their next hire. If they go with a defensive-minded coach, the Colts have to make sure he has an experienced offensive coordinator because they’ll always be an offensive-oriented team as long as Luck is their quarterback.

Will Luck be ready for next season? What direction the Colts go in free agency and the draft first could hinge on Luck’s health. An argument could be made that the franchise is in a holding pattern until it finds out the status of Luck's shoulder. Another surgery could sideline him for up to six months and further bring into question whether he can be the quarterback he was prior to the injury in Week 3 of the 2015 season. Needing to add another established quarterback -- if the Colts don't have faith in Brissett -- would push defense and the offensive line down a notch on Ballard's list of offseason priorities.

Biggest draft need: Pass-rusher. The Colts haven't had a legitimate pass-rush threat since Robert Mathis had 19.5 sacks in 2013. The Colts went into Week 17 with just 23 sacks, which was 31st in the NFL. The offensive line was as bad as it has been in all the years under Pagano, giving up 55 sacks and 110 quarterback hits heading into Week 17. An argument could be made that they need to address every position on the line with the exception of left tackle and center.

Free-agency targets: The Colts have T.Y. Hilton at receiver. That's it. They need to find receivers to help Hilton after Donte Moncrief failed to progress and Kamar Aiken struggled in his first season with the team. Luck, if healthy, needs more targets to throw to outside of Hilton and tight end Jack Doyle.

Running back decisions: Veteran Frank Gore said he plans to play a 14th NFL season. But the 34-year-old, even with his incredible work ethic, likely isn't an every-down back anymore at this stage in his career. Rookie Marlon Mack didn't do enough to show that he's worthy of taking on that role next season unless he takes a substantial leap in the offseason. Veteran running back Robert Turbin is also under contract for next season. The Colts have more pressing needs than taking a running back high in the first round of the draft.

New coordinator? The Colts have to get Luck healthy first. And if that happens, the soon-to-be seventh-year quarterback could be working with his fourth offensive coordinator if Rob Chudzinski is let go with the rest of the coaching staff at the end of the season. There's no questioning Luck's talent, but having to face the possibility of learning a new offense while also overcoming the mental obstacle of not playing a game since Week 17 of the 2016 season is a tough task for any player to take on.