The Notre Dame product picked up things quickly and earned a regular role on special teams, along with consistent reps in sub-packages of defensive coordinator Gus Bradley's scheme.
The consistent Tranquill eventually worked his way into the starting lineup by the end of the season because of his versatility as a solid run defender and as a sticky coverage guy in the pass game.
"He's been very intriguing," Bradley said. "We've kind of had our eyes on him as he's gone through OTAs and into training camp.
"We felt like he's playing more like a veteran player. The way he picks things up, the way he understands the defense, the concepts. Some of the things that we're asking players to do, it seemed like it didn't take him as long to pick it up."
For his effort, Tranquill was voted to the Pro Football Writers of America All-Rookie Team on special teams.
"He earned a role on special teams, earned a role playing in nickel and then earned a role playing in base, and did a really nice job," Chargers general manager Tom Telesco said. "He's smart. He's tough. He runs well. He fits a lot of things that we want to do on defense and he did a really nice job. The kid's tough."
However, Tranquill's playmaking ability was one of the few highlights in an otherwise quiet season for most Chargers rookies.
First-round pick Jerry Tillery worked his way onto the field after having offseason shoulder surgery last March but experienced uneven play. Second-round safety Nasir Adderley finished the season on injured reserve due to a lingering hamstring injury he suffered during his pro day, playing a total of 10 defensive snaps.
Overall, the Chargers got a combined 1,036 snaps (not including special teams) and nine starts from this year's draft class.
Those numbers pale in comparison to a 2018 draft class that produced 1,883 combined snaps and 23 starts as rookies -- including All-Pro and Pro Bowl nods to do-everything safety Derwin James -- helping push the Chargers to a 12-4 record.
With an offseason for the first-year players to get into the weight room and better learn their on-field roles, Telesco looks forward to improvement in 2020.
"It's just hard to generalize it, but you expect them all next year -- they've got to start taking the next step," Telesco said.
According to Pro Football Focus, the Chargers had the 26th most productive draft class in the league last season.
Here's a closer look at each player from the 2019 draft class:
First round: DT Jerry Tillery -- I detailed Tillery's rookie season here. In a nutshell, Tillery didn't make a lot of plays and had trouble holding up against the run at times, but he flashed at the end of the season and showed promise. Most important, he finished the season healthy after missing most of the offseason due to a torn labrum in his right shoulder that required surgery. Tillery finished with two sacks in 15 games played, including three starts, playing 353 defensive snaps. He'll work on improving his play strength and better understanding his role as an interior pass-rusher and run defender this offseason.
Second round: S Nasir Adderley -- Due to a torn hamstring, Adderley played just 10 snaps defensively and 51 on special teams in four games at the start of the season. However, Adderley did flash when he saw the field. Specifically, he corralled an interception and had three pass breakups in the final preseason game against the San Francisco 49ers. Adderley's main goal this offseason is to get fully healthy and earn a role defensively, possibly as a nickel defender or third safety.
Third round: OL Trey Pipkins -- Selected as a developmental prospect out of Division II Sioux Falls, Pipkins was forced into duty because of injuries to Russell Okung and Trent Scott. He performed how you would expect for a young tackle still learning the game, at times showing the ability to hold down the position while other times looking like he did not belong on an NFL field. The good thing is Pipkins played 251 snaps on offense, including three starts, which should help in his development.
Fourth round: LB Drue Tranquill --Playing mostly inside linebacker, Tranquill finished with 64 combined tackles, including four for loss, and a pass breakup in 15 games played, including three starts. He has a chance to lock down a starting role next year at inside linebacker.
Fifth round: QB Easton Stick -- The North Dakota State product was a healthy scratch in all 16 games but on the active roster all season, serving as a scout-team quarterback. The Chargers like Stick's athleticism, smarts and ability to throw on the run. He'll likely get a chance to earn a job as the backup during offseason work and training camp.
Sixth round: LB Emeke Egbule -- Known for his speed, Egbule played just 21 snaps defensively at outside linebacker but also recorded 180 on special teams. Coaches like his athleticism, versatility and untapped potential as an edge rusher. So he has a chance to emerge as a regular contributor in his second season.
Seventh round: DT Cortez Broughton -- The Cincinnati product is another player who flashed potential in limited time, seeing 21 snaps defensively in two games played. Broughton's season was cut short when the Chargers placed him on the non-football illness list after he contracted mononucleosis in Week 8. Broughton has the potential to develop into a disruptive player in the interior of the defensive line.