After a 2020 season that allowed players to transfer with instant eligibility, sit out a season, and return for another, it's hard to keep track of who all will be playing this season in the Big Ten Conference. More importantly, who will be putting on the most impressive performances?

We continue our annual Ranking the Big Ten series today with the defensive ends, a group with players returning from injury, and a few who are looking to make a huge jump in 2021.

Rankings: QB | RB | WR | TE | OG | OT | C

Purdue defensive end George Karlaftis is the top defensive end in the Big Ten entering 2021. Injuries and COVID-19 limited his 2020 season, but his impact when he's on the field landed him on the top of this list.

In his three games in 2020, Karlaftis had eight pressures, three stops, two sacks, four quarterback hits, and two hurries. He was ranked No. 13 in the Big Ten with a PFF's pass-rushing grade of 73.6. The 2020 second-team All-Big Ten selection led Purdue in sacks and tied for second with eight pressures.

During his freshman season in 2019, Karlaftis recorded 55 quarterback pressures with eight sacks, and 29 quarterback hurries in his 12 starts. He also had 35 tackles and 35 stops in those 840 snaps.

Karlaftis's impressive three games in 2020 and his freshman season earned him the top spot on this list and make him the defensive end to watch in 2021.

Ohio State defensive end Tyreke Smith is another up-and-coming player that will have an opportunity to prove himself in 2021. He has started eight games, four in 2020 and 2019, and played in almost every game since he was a true freshman in 2018.

Smith gave the world a glimpse of the damage he can do during the first round of the 2020 College Football Playoffs against Clemson. He had two tackles, one tackle for loss, one sack, and a forced fumble. His game against the defending National Champions earned Smith his highest defense grade of the season (85.8).

In the 2020 season, Smith tallied 33 quarterback pressures, seven tackles, and five defensive stops in 245 snaps. He scored No. 7 in the Big Ten based on PFF's pass-rushing grade (85.1) and No. 9 in total defense (77).

Smith could become one of the best defensive ends in the country with a starting spot of his own and consistent playing time.

Iowa defensive end Zach VanValkenburg is entering his third year at Iowa after transferring from Hillsdale College (Division II), and he's improved drastically from his first season as a Hawkeye to his second.

VanValkenburg's total defense score went from 53.2 in 2019 to 73.8 in 2020. His tackling grade jumped from 41.4 to 66.7. Both his pass-rush and run defense score increased by at least 14 points.

The 2020 second-team All-Big Ten selection started all eight games in 2020 and tied for the national lead with four recovered fumbles. VanValkenburg also recorded 17 tackles, 16 stops, and 19 quarterback pressures, including six sacks.

If he continues to improve his game, VanValkenburg will be one of the best defensive ends in the Big Ten in 2021.

Ohio State defensive end Zach Harrison played in seven games (started one) in 2020 and still managed to rank among the top-five defensive ends in the Big Ten in four of PFF's categories.

He is No. 2 in the overall defensive grade with an 88.8 behind Maryland's Durell Nchami, who played 99 snaps compared to Harrison's 218. The 6-foot-6, 268-pound athlete had the third-highest defense grade (79.5) and the fifth-highest tackle (81.8), and pass-rush grades (86.6).

Last season, Harrison had 22 quarterback pressures, nine tackles, and nine stops. In 2019, he had seven quarterback pressures, including four sacks, 13 tackles, and 14 stops in roughly 60 more snaps.

The former five-star has not disappointed Ohio State in his limited playing time. Harrison should blow away the Big Ten with his talents while playing a more prominent role in the Buckeyes defense.

Michigan defensive end Aidan Hutchinson had his 2020 season cut even shorter by a right ankle fracture at the beginning of his third start of the season against Indiana. In his two games and six snaps, Hutchinson built wonderfully on his impressive sophomore campaign in 2019.

Hutchinson started all 13 games in 2019 and recorded 46 quarterback pressures with six sacks, 47 tackles, 34 stops, and two forced fumbles in 746 snaps. He followed this season with seven pressures, 13 tackles, eight stops in the 149 snaps he played in 2020.

Even with a short campaign, Hutchinson had the second-highest run defense grade in the Big Ten (88.8) and the third-highest tackling grade with an 82.5. He also came in seventh in the overall defensive grade (82.5).

With a full recovery, Hutchinson will terrorize some Big Ten quarterbacks and offenses in the 2021 season.