INDIANAPOLIS -- Hurry back, Andrew Luck! The Indianapolis Colts need you.

The Colts sputtered along on offense all afternoon in their 24-10 loss to the Detroit Lions on Sunday afternoon.

This preseason game wasn’t about the final outcome, but rather looking at individuals and how the different units worked together. All eyes were rightfully on backup quarterback Scott Tolzien because of Luck’s absence. The Colts' offense totaled 27 yards in Tolzien's three series.

Luck’s return from the physically unable to perform list and his availability for the regular-season opener against the Los Angeles Rams continues to hang in the air because he still has to get on the practice field following his January right shoulder surgery.

“He’s actually doing really well,” general manager Chris Ballard said on TV during the game. “His strength levels are probably better right now than they were in the last season that he played. That’s the good news. We’ve just got to continue to process what his doctors and the trainers have going for him and when he’s ready to go we’ll get him out there. I don’t know exactly the timeline, but we want to make sure we do the right thing for Andrew’s long-term health and let him have a big, long career like we think he’s going to have.”

QB depth chart: Tolzien’s afternoon was complete after he went 2-of-5 for 24 yards with a sack and a pass batted down. The change in the depth chart during practice last week carried over to the game, as undrafted rookie free agent Phillip Walker moved ahead of Stephen Morris, who is in his third season, and replaced Tolzien. Walker, who played at Temple, was sporadic throwing the ball. He was only 9-of-20 for 84 yards and was sacked three times, with a couple of those coming because he held the ball too long. “Scott’s had his moments,” Ballard said on TV. “He’s been a little inconsistent, but he’s got to continue to get reps and get better and get the rhythm in the offense. Walker, we think he’s got a lot of talent. He’s a young player and we’re going to continue to work to develop and let him grow.”

When it was starters vs. starters, the Colts looked...: Ballard put a premium on forcing turnovers when he was hired in January. The defense made Ballard happy early when cornerback Vontae Davis got a jump on a Matthew Stafford pass that was intended for receiver Marvin Jones and deflected it. Linebacker John Simon, who spent the past three seasons with the Houston Texans, came down with the interception. That was about the lone highlight for the Colts' starters on offense or defense.

One reason to be concerned: The lack of depth on the offensive line was evident, as they started Deyshawn Bond, an undrafted rookie, at center in place of the injured Ryan Kelly (foot) and Adam Redmond at guard for Joe Haeg (burner). The Colts gave up five sacks, as the starters and the backups gave up way too much penetration to Detroit into the backfield.

Rookie watch: The Colts started two rookies on defense, as Anthony Walker started at linebacker and Nate Hairston started at cornerback because of injuries at those positions. Walker had only two tackles and whiffed on a open-field opportunity on Detroit's first offensive series. It was a little surprising that Hairston, who was selected in the fifth round, started ahead of second-round pick Quincy Wilson. Wilson had a bad angle and gave up a 23-yard touchdown reception along the sideline to Lions receiver Kenny Golladay.

Beat-up team: It's not even the regular season yet and the Colts are hurting. There were some veteran players like Frank Gore and Johnathan Hankins that didn’t play. But receiver Phillip Dorsett, linebacker Antonio Morrison (groin), linebacker Jon Bostic (finger), and rookie running back Marlon Mack (shoulder), to go with Kelly, Haeg and Luck, each sat out with injuries. Veteran Sean Spence left Sunday’s game with a hamstring injury. Ballard said on the TV broadcast that “there’s no question it is a concern” when asked about the team’s rash of injuries.

Locke impressive: New Colts punter Jeff Locke showed off his ability to pin punts deep inside the opponent’s end of the field when he nailed a 54-yard punt that landed at Detroit’s 2-yard line in the first quarter. Locke is replacing Pat McAfee, who surprisingly announced his retirement last winter. Locke averaged 44.5 yards on six punts, with three landing inside the 20-yard line.

Struggle for first downs: It's hard to sustain any drives when you can't pick up first downs. That was the case for the Colts. They had a total of 13 first downs, including having just seven with five minutes remaining in the game. It also didn't help them that they were 4-of-18 on third down.