The Arizona Cardinals saw a significant improvement in their 2020 campaign but still failed to end their four-year postseason drought as they settled for an 8-8 record. Despite barely missing the playoffs last season, head coach Kliff Kingsbury and his squad continue on their rebuilding efforts in hopes of becoming a contender in the years to come.

In a bid to get stronger as a unit. Arizona needed to utilize the 2021 NFL Draft in order to add more talent around their notable players in Kyler Murray, DeAndre Hopkins, and J.J. Watt. Despite hauling in a handful of promising recruits, the Cardinals still committed some errors that could eventually hurt them heading into the 2021 season.

Here are the two mistakes made by the Cardinals in the recently-concluded proceedings:

1. Failing to add more depth in the interior offensive line

The Cardinals started the offseason on the right note when they traded their 2021 third-round pick in exchange for three-time Pro Bowl center Rodney Hudson and a seventh-round selection. However, the team's interior offensive line continues to lack depth despite adding an experienced veteran to the unit.

Arizona continued to make moves as they brought back veteran guard Justin Pugh and added former Buffalo Bills guard Brian Winters to their roster. However, it remains to be seen if the aforementioned names will be good enough to protect Kyler Murray under center next season.

In the draft, the Cardinals ultimately lost their chances to land a capable guard when they chose to select Purdue WR Rondale Moore with the 49th pick in the second round. They also didn't have a third-round pick that they could've used to nab a player like Ohio State guard Wyatt Davis who eventually went to the Minnesota Vikings at the 86th pick.

Ultimately, Arizona waited until the seventh round just to secure an offensive lineman in Penn State center Michal Menet who was drafted with the 247th pick. The Cardinals can only hope that both Justin Pugh and Brian Winters will be effective in the trenches and provide much-needed pass protection for Kyler Murray in order to help him elevate his game in their campaign next season.

2. Missing out on talents at the tight end and running back positions

The defensive rotation was obviously the main target of the Cardinals in the 2021 NFL Draft as five out of the seven total players that they selected are all playing on that end of the field. Though they definitely beefed up their defensive rotation, they continue to run thin on the other areas of their offensive attack, most especially their tight end and running back groups.

Heading to the 2021 season, the Cardinals still have veteran Maxx Williams as their starting tight end. Despite being a tenured player, he doesn't exactly provide much impact on the field. Last season, the Minnesota product only recorded a total of 102 receiving yards on eight touches along with a lone touchdown through nine games played.

Backing him up is former undrafted tight end Darrell Daniels who has yet to see significant action on the field despite playing in his fourth campaign last season.

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To add to their woes, the Cardinals' running back corps got thinner after former RB1 Kenyan Drake chose to relocate to the Las Vegas Raiders in the offseason. His departure will be a huge loss for Arizona, given that he just concluded a breakout campaign last season with a total of 955 rushing yards on 239 carries and 10 touchdowns in 15 appearances.

The Cardinals then attempted to recuperate from the loss by adding an intriguing talent in James Conner who previously played for the Pittsburgh Steelers. Similar to the past few years, injuries continued to hurt his production as he settled for 721 rushing yards on 169 touches and six touchdowns in 13 appearances last season. It remains to be seen if he can replicate Drake's production and remain healthy in 2021.

Coming off the bench will be a 25-year-old rusher in Chase Edmonds who has shown promise in his first three seasons in the league. In 2020, he notched 448 rushing yards on 97 attempts and a touchdown in 16 appearances last season. He also exhibited his ability to catch the ball as he contributed four receiving touchdowns last season. Despite lacking in experience, his development as an incoming fourth-year player will definitely make an impact on Arizona's rushing group next season.

The Cardinals' decision to stack their WR rotation with the addition of rookie pass-catcher Rondale Moore certainly left their other offensive groups with shallow depth. After failing to add talent in their tight end and running back units, the Cardinals are expected to heavily rely on their veteran holdovers to deliver on the field next season.