SANTA CLARA, Calif. -- Late in Tuesday's joint practice against the Tennessee Titans, San Francisco 49ers quarterback Brock Purdy dropped back, scanned the middle of the field, and unleashed a deep pass. At first glance, the ball seemed destined for a trio of Titans defenders poised to intercept. Then rookie receiver De'Zhaun Stribling burst through the congestion, snatched the ball in stride, and raced downfield for what would have been a long touchdown. That throw, risky against multiple defenders, signaled Purdy's growing confidence in the first-year wideout.

"He's a really smart dude," Purdy said. "He gets the game of football. Sometimes guys come in, they're talented and stuff, but to understand the speed of the NFL and how defenses operate, it can be hard for them to get with it quick. Eventually they get there, but Strib has been a guy that has come in and shown he understands it ... It is preseason, so we'll see once we get to the season, but right now I have a lot of trust in him."

That trust has transformed Stribling from an intriguing draft pick into a necessity. After a brief three-day bout with hamstring tightness, he has become a lifeline for a depleted receiver room that lost Ricky Pearsall to a season-ending knee surgery. In San Francisco's preseason opener against Tennessee, Stribling led the team with seven receptions for 62 yards. According to ESPN Research, he is the first rookie in the past decade to record seven or more receptions in the first half of his team's first preseason game.

Head coach Kyle Shanahan noted Stribling's debut with measured praise. "It seemed good," he said. "I thought he struggled a little bit on the first drive, but he got three drives after that. It seemed like he executed all the stuff that went to him, and I liked how his hands looked out there and played physical."

Stribling's arrival in Santa Clara raised eyebrows when the 49ers selected him at No. 33 overall after trading down twice to exit the first round. He ranked 15th among wide receivers in ESPN's prospect rankings but was the sixth taken off the board. The 49ers' brass saw his physical blueprint as something the team lacked: boundary size blended with legitimate vertical speed. At 6-foot-2 and 207 pounds, Stribling is big enough to block defenders in the run game and make plays over the middle. His 4.36-second 40-yard dash, the eighth fastest among all receivers at the NFL combine, allows him to stretch the defense deep.

Backup quarterback Mac Jones borrowed a nickname from MLB outfielder Shane Victorino to describe that speed. "I call him the 'Flyin' Hawaiian' because he's so fast," Jones said. "He has like a second gear when the ball's in the air. Some guys are really fast, but when the ball goes up and your eyes go up, you slow down, but he doesn't do that, so it's pretty impressive."

Since Shanahan and general manager John Lynch took over in 2017, the 49ers have drafted 14 wide receivers. Only Jalen Hurd and Jauan Jennings stood taller. Only Hurd, Jennings, and Deebo Samuel Sr. weighed more than Stribling. And only Danny Gray (4.33 seconds) ran a faster 40-yard dash in the predraft process. While every team wants bigger and faster receivers, the Niners made it a point to get one this year amid another makeover of the receiver room.

"That's the thing when you look at receivers, usually you're going to get a guy who's maybe big and physical, but he doesn't have the speed," receivers coach Leonard Hankerson said. "... It's rare to get a guy like Strib that has everything: big, strong, physical, and he can run."

But physical abilities alone don't earn early playing time in Shanahan's system. The team has long avoided plugging young wideouts into a single position, instead asking them to learn all three spots (F, X, or Z) before deciding where to play them. That workload can faze some players, but coaches and teammates say Stribling isn't bothered. His strong impression came from a routine he developed after the offseason program. Each day, he studies film and says every playcall out loud or has someone recite it to him. Then he writes it down or draws the play to visualize it. He goes through the playbook repeatedly, occasionally asking his mother or girlfriend to quiz him. He even joined fellow wideout Jordan Watkins for throwing sessions with Purdy and Jones in Nashville before camp. Offensive coordinator Klay Kubiak said Stribling's football acumen was "one of the reasons why we really love him," adding that Stribling "absorbs football naturally."

Although learning all three positions for that many plays could be confusing, Stribling sees it as an advantage. "Playing a bunch of the spots allows me to see the full picture of the play, not just focusing on one spot," he said. "If I know the whole concept, I kind of know what I have to do at either F, X or Z. I feel like I'm very confident wherever I'm at."

Now the question is where Stribling will fit. In college stops at Washington State, Oklahoma State, and Ole Miss, he did a little of everything. He ran most of his 1,744 routes across three seasons from the outside (1,358), followed by 372 routes from the slot. He even ran 10 routes as an in-line tight end and four out of the backfield. With the 49ers, free agent signing Mike Evans will be the "X" receiver, a spot Stribling might one day inherit. Pearsall was supposed to be the "Z," but his injury leaves that spot open. Hankerson indicated that Stribling projects more to the "F" (slot) position that Jennings filled, adding that there "may come a time and point" for him to play the "Z." Of his 15 routes in the preseason opener, Stribling ran 10 from the slot and five from the outside.

Regardless of where he lines up, Stribling is on track to be one of San Francisco's top receivers right away, provided he continues piling up productive practices and performances in the last two preseason games. "We need to get him ready to play an NFL game, and it takes awhile for rookies to do that," Shanahan said. "That's why a lot aren't ready for Week 1 ... I think each day he's got better and better. Hopefully he doesn't have any injuries, so he can continue getting those days in for Week 1, and if he does, feel real confident about him."