KUSA – Let’s assume all goes well with Case Keenum.

The Broncos have their quarterback who can play well enough to win and not commit the costly turnover.

Let’s presume Bradley Roby makes a smooth transition in replacing Aqib Talib, Vance Joseph pushes a few more correct buttons in year two as head coach, Brandon McManus rebounds from an off year,

Bradley Chubb is indeed all that, and the receiver duo of Demaryius Thomas and Emmanuel Sanders return to form with Keenum as their quarterback.

The 2018 Broncos still have plenty of question marks and concerns.

On Tuesday, we listed three areas where the Broncos made significant improvements – one for each phase of special teams (Tom McMahon), offense (Keenum) and defense (Chubb).

Dec 14, 2017; Indianapolis, IN, USA; Denver Broncos tight end Jeff Heuerman (82) reacts to scoring a touchdown on a 54 yard pass play against the Indianapolis Colts during the 3rd quarter at Lucas Oil Stadium.
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Now we look at four major question marks: One, can Jeff Heuerman and Jake Butt step up to give the Broncos a top 15-caliber tight end duo? Two, how much will Garett Bolles improve in year two at left tackle and can veteran Jared Veldheer finally bring adequacy to the right tackle position? Three, can nose tackle Domata Peko continue to play at a high level at 33 years old? Four, given the addition of two rookie receivers and Jordan Taylor’s offseason hip surgery, who will be the Broncos’ returner?

Yes, we list one more concern than highlight. Why? 5-11. There are always more question marks than solutions for a team coming off a 5-11 season.

Oct 30, 2017; Kansas City, MO, USA; Denver Broncos wide receiver Jordan Taylor (87) drops a pass during the game against the Kansas City Chiefs at Arrowhead Stadium.
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A look at the Broncos’ Big 4 question marks or concerns heading into 2018:

Tight end

Either the good teams have a very good tight end or they’re trying to get one. The Broncos have been trying to find one since Owen Daniels beat Jamie Collins twice for touchdowns in the 2015 AFC Championship Game.

Virgil Green was allowed to leave for free agency in part because the Broncos believe Heuerman and Butt are ready to step up.

Aug 12, 2016; Glendale, AZ, USA; Arizona Cardinals offensive tackle Jared Veldheer (68) against the Oakland Raiders during a preseason game at University of Phoenix Stadium.
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Heuerman has been knocked for his disappointing production through his first three seasons but what can a third-round draft pick do when he tears up his knee during a rookie minicamp kickoff coverage drill?

He had 9 catches for 141 yards and 9 catches for 142 yards each of the past two years. He looked great while catching a 54-yard touchdown from Brock Osweiler at Indianapolis last year but he needs to flash a few more big plays to become a legit, No. 1 NFL tight end.

“I think just getting into a rhythm and getting into a groove,’’ Heuerman told a Denver media contingent Tuesday. “You were talking about playing with three different quarterbacks and going week to week last year. It’s kind of tough sometimes getting into a rhythm and getting into the groove of things. Hopefully with Case we can get into a good rhythm and build on that week to week. Hopefully it will take us deep.”

Butt was considered a top 50 player in the 2017 NFL Draft until he suffered his second, torn right ACL in Michigan’s bowl game his senior year. The Broncos drafted him in the fifth round but Butt missed his entire rookie season to recover from knee surgery.

It’s best to manage expectations for him this season, as 20 receptions may be more realistic than 45. It’s the 2019 season that the Broncos may get the best of Butt.

Offensive tackle

The reviews of Bolles’ rookie season are mixed. His 10 holding penalties tied Cleveland’s Shon Coleman for most in the NFL and his 15 total penalties were tied for second. Still, Bolles doesn’t threaten the league’s penalty lead if he didn’t start all 16 games against some of the NFL’s top pass rushers.

Then there’s the right tackle position, otherwise known as the Black Hole of the Broncos’ starting lineup. Since Orlando Franklin was moved from right tackle to left guard following the Broncos’ Super Bowl 48 debacle, right tackle starters have been Chris Clark, Paul Cornick and Louis Vasquez in 2014; Ryan Harris and Michael Schofield in 2015; Donald Stephenson and Ty Sambrailo in 2016; Menelik Watson, Allen Barbre, Cyrus Kouandjio and Stephenson in 2017.

That’s 10 right tackles in four seasons.

The Broncos made a small trade with Arizona this offseason in hopes Veldheer can solve their right tackle position problem this season.

Defensive tackle

It was a little surprising the Broncos didn’t reinforce this position during the offseason. Domata Peko did bounce back nicely after 11 years with Cincinnati and his release following the 2016 season. He was especially strong against the run in the first-half of the 2017 season.

Nov 19, 2017; Denver, CO, USA; Denver Broncos nose tackle Domata Peko (94) reacts in the second quarter against the Cincinnati Bengals at Sports Authority Field at Mile High.
Ron Chenoy-USA TODAY Sports

The Broncos will need either his cousin, Kyle Peko, or undrafted rookie Lowell Lotulelei to make significant contributions this year.

Returner

After trying to hit a home run with rookie Isaiah McKenzie as a punt returner last year, the Broncos instead got too many strikeouts.

Oct 1, 2017; Denver, CO, USA; Denver Broncos wide receiver Isaiah McKenzie (84) returns a punt for a gain in the third quarter against the Oakland Raiders at Sports Authority Field at Mile High.
Ron Chenoy-USA TODAY Sports

Taylor may have been a singles or doubles-type returner, but he never whiffed. If Taylor isn’t ready to go by week 1, will the Broncos return to McKenzie? The Broncos will also give undrafted rookie Phillip Lindsay a chance.

Kick returner Cody Latimer left for free agency and the New York Giants, leaving another opening.

The 2018 Broncos still have plenty of question marks and concerns.