Sunday's practice was off to a great start for the Las Vegas Raiders.

Alex Leatherwood was on his A-game after controversial takes surrounding the right tackle on Saturday. Nate Hobbs continued his campaign to be a leading figure in the Raiders' secondary, while the receiving unit continued to flourish as a whole.

With things heating up (literally) in Henderson, Nevada, a rainstorm blew in and ended the practice. Even worse than practice being cut short, inside linebacker Micah Kiser suffered a leg injury which landed him on IR.

Kiser is far from a household name, so it's easy to think little of the situation. For the Raiders, this is a massive blow.

For the first time since 2017, Las Vegas is switching to a 3-4 front. Heading into the 2022 offseason, the Raiders' roster housed zero linebackers with experience in this front. Once free agency started, the Silver and Black brought in Micah Kiser, who was the first linebacker rostered with 3-4 experience.

Now, down an inside linebacker, the Raiders are back to the drawing board. Luckily for Las Vegas, the team also brought in Kenny Young and Jayon Brown, with the latter almost certainly earning a starting role in the 3-4 front.

Who will replace Kiser, though? Here are two immediate options the Raiders have.

Micah Kiser replacements for Raiders

2. Kenny Young

The first of the two options to replace Kiser is the aforementioned Kenny Young.

Newcomer Jayon Brown is practically guaranteed to earn a starting inside linebacker role in the Raiders' 3-4 scheme, but who will the other starter be? The most probable answer is Denzel Perryman, who earned a trip to the Pro Bowl in 2021.

Head coach Josh McDaniels has already begun singing praises of Perryman and his leadership as well. Although the 29-year-old has no experience in the Raiders' new front, McDaniels claims Perryman is adapting quick and up for the new challenges.

This ultimately leaves Kenny Young on the outside looking in, replacing Micah Kiser as the first rotational inside linebacker.

Kiser and Young have a history in the NFL together; the coincidences are almost scary. In 2019, Young was traded to the Los Angeles Rams, where Kiser was already playing ball. Mid-2021, after two years of being together, Kiser was signed by the Denver Broncos off the Los Angeles Rams' practice squad. One month later, in October, Young was traded to Denver, reuniting with Kiser.

Now in 2022, both end up on the Las Vegas Raiders, continuing their journey together.

Young started 19 contests in the last two years, including seven starts in 2021 for the Super Bowl champion Rams. In these two seasons, Young totaled 127 tackles with three pass breakups, three sacks and an interception.

The Raiders are down big without Kiser, but Young can do more than help stop the pain. The inside linebacker brings starting experience to a linebacker core changing their defensive scheme.

1. Darien Butler

Undrafted free agent camp sensation Darien Butler is another option the Raiders have.

Butler is a versatile linebacker who can play both inside and outside, excels in coverage and holds his own weight against the run. His total skill set is what the Raiders need, although at 5-foot-10 Butler is a bit undersized.

His lack of size hasn't stopped him throughout camp, though. Butler has been one of the most noteworthy players through camp, even earning run with the first-team defense this past weekend.

The former Arizona State linebacker also made the first interception of training camp, as well as a hit on rookie running back Brittain Brown that woke the Silver and Black up.

Through college, Butler was a jack of all trades. He was a top-50 graded linebacker in the FBS and earned the honor of being a team captain in three of his four years at Arizona State. Butler became the only true sophomore in school history to receive this honor.

During his senior year, Butler earned a 87.7 coverage grade, per Pro Football Focus. This grade ranked No.1 in the Pac-12 among linebackers. The ASU linebacker was also responsible for 18 tackles either behind or at the line of scrimmage. Out of all the defenders in the Pac-12, this was the second-highest total.

Butler was already forcing himself onto the roster with superb camp play, but with Kiser now on IR, it seems unavoidable. The Raiders need a replacement for Kiser, and Butler is proving he's the right man for the job.