Kyle Terada-USA TODAY Sports

Kyle Terada-USA TODAY Sports

49er fans are well aware that Aaron Lynch has been suspended by the NFL for the first four games of the season, under its discipline program for substances of abuse. Lynch's assertion that the test was the result of a diluted sample, caused by him being overhydrated, is little comfort to fans who expected to see the team's best edge rusher leading an improved defensive front to a significantly improved season. Most 49er fans are familiar with the names Eli Harold and Cornelius (Tank) Carradine, as these two players will attempt to step in for Lynch during his absence.

Coming out of college, Eli Harold was an under sized (240-245 pounds) power rusher, who also possessed the speed and agility to pursue the football sideline to sideline. In his rookie season with the 49ers, he was given opportunities in the base personnel package, as well as sub packages on passing downs. While his athleticism flashed and he displayed a high motor, his lack of size created difficulty in setting the edge on outside run plays, and similarly made it difficult for him to walk offensive tackles back into the pocket with his bull rush. He didn't show up much on the stat sheet, but coaches were encouraged by athleticism, attitude, and energy. He was asked to bulk up in the offseason.

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When Tank Carradine entered the draft, he was a gifted speed-to-power edge rusher who was well on the large side, for that type of player. He was also recovering from surgery to repair a torn anterior cruciate ligament (ACL). Carradine's rookie season was essentially wiped out, as he used the year to continue his recovery from surgery, learn the defense and his responsibilities in a new position (3-4 DE), and add weight to his already large frame to fulfill his responsibilities as a 2-gap 4 technique. The following 2 years, he was still trying to adjust to his new role as a 4-technique defensive end.

While Carradine was a defensive end in college, his role in Florida State's 4-3 called on him to maintain a wide shade and attack the offensive backfield, playing with at least half of his body in space, using speed and power to disrupt the offense. The 49ers were asking him to play directly over the offensive tackle, occupying both of the gaps on either side of the tackle, while staying on the line of scrimmage to occupy double teams. Eventually, the 49ers realized that Carradine was not suited to clog lines in the interior of the defense, and they asked him to cut weight and return to the role of edge defender, where he had found tremendous success in college.

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Fast forward to 2016, and the two players have similar dimensions. They are both tall (Harold: 6'3"; Carradine 6'4") and right around 265 pounds. They are both working at the same position behind Aaron Lynch, and they both have impressive tools to bring to the role.

I came away from yesterday's practice surprised and impressed by Harold's ability to maintain his mobility and athleticism after gaining all of the weight he did. He drops fluidly into his coverages, and accelerates easily and instantly. He changes direction just as impressively as he did at 245 pounds. He carries the weight with even distribution about his body, and his calves look enormous now. His added size now gives significant force to his aggressive punch when he engages the offensive tackle. While he was able to disrupt several offensive plays in the backfield, he separated himself as the best OLB moving in space.

Carradine looks less comfortable in space, and it was almost unfair to watch his repetitions in pass drop drills immediately after Harold went. While Carradine is much faster and more agile than he was at 290 pounds, he looks slow and clunky when compared to Harold; however, while Tank is unimpressive moving backwards, he is a constant disruption when he moves forward. He never seemed to be contained on passing plays, and runs to his side were doomed. While it is only fair to note that the 49ers practiced in shells yesterday, so the offense might not have been able to block at 100%, Carradine was active, relentless, and always moving forward when he was called upon to get into the backfield.

So, who replaces Aaron Lynch? While it has been reported that Arik Armstead and DeForest Buckner have rotated out to the edge in passing situations, I didn't see that occurring the majority of the time yesterday. It was still primarily OLBs on the edge, and they looked good. With Harold's athleticism and added size/strength, it makes a lot of sense for him to get the nod in most base downs. While he can be effective as an edge rusher in sub packages, I think Carradine has the edge (see that?) here, and it provides an opportunity for Harold to stay fresh through the game if he gets to rotate out for some snaps on defense. If both of these players prove themselves, they could eventually spell Ahmad Brooks on the other side, and the resulting three-man rotation could keep the group fresh on a defense that is likely to see an increased number of snaps this year. It is likely that one or both of Carradine and Harold will perform well enough in Lynch's absence to cut into Brooks' repetitions once Lynch returns, which is exactly what occurred during Aldon Smith's suspension to allow Aaron Lynch to emerge as a playmaker for the 49ers,

Who do you think the 49ers will use to hold Lynch's place until he returns? Let me know in the poll below.