If the season started tomorrow, here would be the 49ers’ starting defensive line: Nick Bosa, Jordan Elliott, Evan Anderson and Yetur Gross-Matos.

That’s a bottom-five defensive line in the NFL on paper.

Bosa still is a good player, but he’s not the great player he was a few years ago, and he’s on the field for fewer than 80 percent of the defensive snaps. So they need other good defensive linemen. And they have none.

That’s because they recently released three starters: Javon Hargrave, Maliek Collins and Leonard Floyd. And surprisingly, the 49ers signed zero replacements. They reportedly tried to sign Joey Bosa, but the Bills outbid them so he signed with Buffalo. Meanwhile, Floyd signed with the Falcons.

It’s painfully obvious that the 49ers plan to draft lots of defensive linemen early in the Draft. They have no choice given their moves in free agency. They signed cornerback Tre Brown and safeties Jason Pinnock and Richie Grant, so they can wait to draft those positions. They don’t necessarily need to draft Day 1 starters in the secondary.

But on the defensive line, the 49ers need to draft three Day 1 starters. And good ones. That’s incredibly difficult to do.

The 49ers drafted well last year but drafted quite poorly the previous three. Even the best drafting teams miss on roughly 50 percent of their picks.

If the 49ers miss on half of their defensive line picks this year, they’ll struggle to make the playoffs.

They have to be perfect.