INDIANAPOLIS – For the second time in 12 months, a major component of Frank Reich’s coaching staff has left the building.

First, it was Nick Sirianni. One year and three days ago, the Indianapolis Colts’ offensive coordinator was named head coach of the Philadelphia Eagles.

Next, Matt Eberflus. Thursday, the team’s defensive coordinator filled the vacant head coaching position with the Chicago Bears.

Losing valued coordinators can result in seismic philosophical shifts within a franchise.

That wasn’t the case when Sirianni relocated to Philly. Reich is the architect of the Colts’ offense and the game-day play caller. The addition of a new coordinator – Marcus Brady – was seamless. Status quo prevailed.

Finding a successor for Eberflus could result in turning the page in defensive approach. Also, d-line coach Brian Baker will not be retained, and it’s possible Eberflus will bring one of his colleagues in Indy to Chicago as coordinator.

Perhaps Reich and general manager Chris Ballard are ready to move away from Eberblus’ 4-3 scheme that leaned heavily on zone coverage and only occasionally blitzed.

It’s hard to imagine a dramatic shift, though, considering the defensive personnel has been tailored for a 4-3 alignment. One thing Ballard mentioned in his post-season meeting with the media was Eberflus relying more on man coverage over the second half of the season.

“I thought when we started playing more man-to-man down the stretch, the completion percentage and the quarterback’s QBR wasn’t as high as it was early in the season,’’ he said. “That’s something I know Flus is looking into.’’

The ability to be flexible and efficient in “sub” packages will be critical for whomever replaces Eberflus. Nowadays, base alignments are less defining.

“Everybody ends up in nickel and dime defense anyway,’’ Ballard said. “You end up with a four-man front.’’

Regardless the successor and the scheme he brings to Indy, one area absolutely, positively, without a doubt must improve.

Edge pass rush.

There are so many areas of distinction by Eberflus’ defense over the past four seasons: 10th in fewest points allowed (22.2), 10th in yards (340.5), 4th against the run (99.9), 2nd in total takeaways (107) and tied-3rd in interceptions (64).

But there have been other areas that have held the defense and the entire team back: completion percentage (a league-high 67.9% allowed), third-down conversion rate (41.6%, 9th-worst), passer rating (93.1, 15th-worst) and sacks (152, 18th).

The edge pass rush has remained a debilitating factor.

Ballard accepted much of the blame after the Colts’ collapsed over the final two weeks, and primarily focused on two areas.

“Our passing game has to be better; just has to be,’’ he said. “And on defense we’ve got to be able to rush the passer better.

“It’s a passing league. You have to be able to affect the passer, and you’ve got to be able to throw it.’’

Too often, the Colts were unable to affect the passer. Too often, they were unable to finish games because their edge rushers couldn’t generate a drive-halting sack or couldn’t force the quarterback into a hurried throw or mistake.

From week 5 through week 14, the Colts built double-digit leads. Three times they were unable to fend off fourth-quarter comebacks. That includes the 31-25 overtime debacle at Baltimore in week 5. They led 22-3 late in the third quarter only to see the defense allow four consecutive touchdown drives and a pair of two-point conversions.

Make a defensive play or two during that stretch, and there’s no dramatic comeback, or colossal collapse.

In the final six weeks of the season, the Tampa Bay Buccaneers and Las Vegas Raiders exited Lucas Oil Stadium with victories on the strength of game-winning fourth-quarter drives.

And then there’s this. In the first three quarters of games, the Colts mounted a plus-135 points advantage (344-209). In the fourth quarter and overtime, they were a minus-40 (107-147). The 147 points surrendered in the fourth quarter were the 3rd-most in the league.

“ . . . 2-5 in one-score games,’’ Ballard said with a frustrated shrug. “We’ve got to do a better job of finding a solution how we finish these games.’’

It doesn’t take a football savant to realize more effective edge rushers would enhance the ability to finish games. Get a lead, then turn the pass-rush loose.

“There’s things we need to be better at,’’ Ballard said. “We need to affect the passer.’’

The Colts ranked 26th in sacks per pass play last season, and the 33 were down from 40 a year ago and the fewest during Eberflus’ tenure.

DeForest Buckner led the way for a second straight season, this time with 7 sacks. But it’s hardly a ringing endorsement for a defense when its tackle – All-Pro, Pro Bowl, whatever – is the prime pass-rush catalyst.

“It starts with me,’’ Buckner said. “The one-on-ones that I do get, which are slim throughout the game, I’ve gotta win. I’ve got to be more consistent with that.

“Each and every guy in the room, we’ve got some things to work on in the offseason individually. And I believe with the guys we have in the room and the work ethic, we’ll get it done in the offseason, and we’ll come back better.’’

The Colts headed into 2021 committed to their young rushers: first-round pick Kwity Paye; second-rounder Dayo Odeyingbo, who was in rehab mode at the start of the season after tearing an Achilles tendon; Kemoko Turay, Tyquan Lewis, Al-Quadin-Muhammad.

Two of the top pass rushers in 2020 – Justin Houston and Denico Autry – departed via free agency.

Ballard admitted it might have been prudent to add a veteran pass-rush presence to last season’s unproven bunch, and that might steer his approach during the upcoming offseason.

Paye’s influence increased as the season unfolded, and he became more comfortable in Eberflus’ scheme – 4 sacks, 10 quarterback hits – and there’s every reason to believe he’ll develop into a perennial double-sack threat.

“The second half of the season I feel he came into his own,’’ Buckner said. “I feel the game slowed down for him a little bit. He was able to show his ability to rush the passer and affect the game and make those plays that we drafted him here for.’’

But what can’t be ignored: excluding Paye and Odeyingbo (insufficient evidence after 10 game), the Colts’ personnel department has had a difficult time uncovering reliable pass-rush talent in the draft.

And that issue has spanned the regimes of Ballard, Ryan Grigson and the tailend of Bill Polian.

Since 2010, the Colts have sought edge/pass-rush help in the first three rounds of the draft eight times, nine if you include Lewis.

Not one has panned out, and that includes first-rounders Bjoern Werner (24th overall in 2013) and Jerry Hughes (31st overall in 2010). Werner had 6.5 sacks in 38 games. Hughes had 5 in 40 appearances before being traded to Buffalo, where his career took off.

Turay, a 2018 second-rounder, has 12 sacks in 38 games while battling a variety of injuries and will be a free agent in mid-March. Tarell Basham, a third-round in ’17, had 2 sacks in 16 games before being waived midway through his second season.

Lewis had established himself as a valuable movable part in the d-line rotation last season only to have his fourth year end in week 8 when he tore his right patellar tendon. He’ll be a free agent in March and might be re-signed.

Ballard’s vow to keep his d-line stocked won’t diminish, but he bristled a bit when the need of a top-end edge rusher was broached.

“We just want them to come in and play really good football, be consistent, be part of the wave,’’ he said. “You’ve gotta have eight of them. I failed us. I didn’t do a good enough job of making sure we consistently had the right eight this year.

“(But) to think the next one’s going to be the next Dwight Freeney or Robert  Mathis, I don’t know if that’s always being realistic. Is that something you shoot for? Yeah.’’

He remains bullish on Paye and Odeyingbo.

“With the pass rush, we did draft two young players,’’ Ballard said. “Now I know y’all want them to be the next Deacon Jones right off the bat. That ain’t real.

“Let’s let these young guys develop.’’

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You can follow Mike Chappell on Twitter at @mchappell51.