SANTA CLARA >> Picture this: Nick Bosa bursts off one side of the 49ers’ rebuilt defensive line, Yetur Gross-Matos shifts inside to come up the gut and a hot-shot rookie speeds in from the other defensive end spot as they all collapse the pocket.

And who will that rookie be?

That is for the 49ers to discover, presumably with their first-round draft pick come Thursday night, April 24.

Bosa remains their premier defensive lineman, but it’s now by default.

The 49ers’ offseason purge saw them release the trio that started next to Bosa in last season’s opener — Javon Hargrave, Maliek Collins and Leonard Floyd.

To maximize Bosa’s production, the 49ers are back to their annual search for a complementary defensive end. In recent years, they have run through Dee Ford, Kerry Hyder, Arden Key, Charles Omenihu, Samson Ebukam, Clelin Ferrell, Randy Gregory, Chase Young and Floyd.

Floyd was a 17-game starter in his lone 49ers season, but outweighing his durability and 8 ½ sacks were this year’s $1.5 million in salary cap savings.

Floyd came aboard last year on a two-year deal, as did Gross-Matos, who’s now penciled in as the starter opposite Bosa. Gross-Matos overcame a preseason knee injury and had a three-sack outburst in the 49ers’ final win last season (over the Bears), but his versatility to shift inside on pass downs creates the need for a certified speed demon on the edge.

Once the 49ers passed on drafting a defensive end last year, their rationale was this, as explained then by co-director of player personnel R.J. Gillen: “With how we saw the board developing and going into draft meetings, where we were picking, there were gaps in the board at that position, so that was a position we decided to attack in free agency.”

Now they must attack in this draft, and here are five candidates they may consider at No. 11 overall, with the first of their 11 picks:

Carter, Penn State

• 6-foot-4, 250 pounds

He could go as high as the No. 2 overall pick, unless his stock tanks as a result of shoulder and foot injuries. His edge-rushing prowess showed last year with 12 ½ sacks, 66 pressures and 23 1/2 tackles for loss.

James Pearce Jr., Tennessee

• 6-5, 252 pounds

He ranked first at the combine among edge rushers with a 10-second split of 1.56 seconds.

His lean, relentless frame might remind some of Aldon Smith (No. 7 pick in 2011). The No. 11 pick may be too high for him, and the second round may be too late.

Shemar Stewart, Texas A&M

• 6-5, 267 pounds

He had only 1 ½ sacks each of the past three seasons, so the 49ers would be gambling on his potential to finish better and complement the similarly sized Bosa (6-4, 266 pounds). But Stewart’s tenacity in run support can’t be overlooked in the 49ers’ reboot.

Mykel Williams, Georgia

• 6-5, 267

Is he a read-and-react defensive end or the 49ers’ preferred get-the-heck-off sprinter? He ran a 4.7-second 40-yard dash at his pro day, which wouldn’t have cracked the top-10 among edge rushers at the combine.

Mike Green, Marshall

6-3, 251 pounds

His size is similar to Dee Ford, the 49ers’ 2019 bookend opposite of Bosa. He made second-team All-America last season (17 sacks), having transferred to Marshall in the wake of sexual-assault allegations at Virginia. He excelled in the Senior Bowl, where 49ers assistant K.J. Wright was working with the defensive linemen.

Roll call >> Donovan Ezeiruaku (Boston College), Landon Jackson (Arkansas), JT Tuimoloau (Ohio State), Jordan Burch (Oregon), Jack Sawyer (Ohio State)