MINNEAPOLIS – The timetable is unknown for Irv Smith Jr.’s return from the meniscus injury he sustained in the Minnesota Vikings’ final preseason game. The rising star at tight end could be sidelined several weeks and miss a handful of games, or he could be subjected to a months-long recovery process. That’s the nature of this injury.

Smith will undergo surgery this week, and until team doctors get a look inside his injured knee, no one can know for sure how long he’ll be out. But Minnesota couldn’t afford to play the wait-and-see game, not with how critical the tight end position is to the success of this offense.

Minnesota sent a 2022 fourth-round pick to the New York Jets on Tuesday in exchange for fourth-year tight end Chris Herndon and a 2022 sixth-round selection. The move reflects how seriously the team is taking the potential that Smith could miss considerable time.

So for now, an offense that deployed the third-most two-tight end sets in 2020 has at least one other starting-caliber tight end next to Tyler Conklin.

As Mike Zimmer processed just how significant Smith’s loss could be earlier this week, the Vikings coach offered a blunt assessment of Minnesota’s tight end depth.

“Yeah, well, it’s not very good,” Zimmer said.

At the conclusion of cut-down day on Tuesday, the Vikings still have Smith on the 53-man roster (though he’ll likely get moved to injured reserve with the option of being designated to return after three weeks) along with Conklin, Herndon and Brandon Dillon, a third-year player who has appeared in four career games and caught one pass for six yards.

Other tight ends like Zach Davidson and Shane Zylstra, who were waived Tuesday, could find their way onto the practice squad, but no matter how many tight ends the Vikings keep in their building, filling the void left by Smith and the promise he presented entering his third season will be difficult.

Smith flashed his potential during the final four games of the 2020 season when he stepped into a TE1 role in place of an injured Kyle Rudolph. He hauled in three touchdowns on 20 targets from Weeks 13-16, and he finished with 30 catches for 365 yards and five scores in 13 games last season.

Coaches and teammates lauded him for how explosive he looked in practice the last four months. Quarterback Kirk Cousins appeared to have found a new security blanket in the red zone after Smith took in pass after pass for scores throughout training camp.

But the Vikings don’t know how long they’ll be without the player they anticipated often being their No. 3 receiver, so they signed a player they hope can help shoulder the load in the meantime.

Herndon, a former fourth-round pick for the Jets, showed a lot of promise as a rookie (39 catches, 502 yards, 4 TDs) in 2018, but he hasn’t come close to that since. Through most of 2020, the tight end struggled with drops and fumbles and became better served as a blocking tight end. He turned the corner by the end of the season (31 catches, 287 yards, 3 TDs in total), but he fell down the depth chart in training camp this summer and found himself on the way out of New York.

Minnesota is also relying heavily on Conklin. Zimmer said this spring that he anticipates Conklin having a far bigger role in the offense in 2021.

“I think me and Irv are a lot more similar than people think,” Conklin said. “We both can run well, we both run routes really well. I think we just do it in different ways. I think we can both be split out wide and run routes like receivers.”

Additionally, Zimmer said the Vikings could tap into their receiver depth with Smith out and use three-receiver sets.

That’s asking a lot for the NFL’s only offense that used 11 personnel -- three-receiver sets -- less than 40% of the time in 2020. According to Football Outsiders, the Vikings finished last by throwing only 9% of passes to targets designated as “other wide receivers,” i.e., not Justin Jefferson or Adam Thielen.

Do they have the capability to deploy three-receiver sets? Sure. But a lot of that will depend on how healthy Dede Westbrook is come Week 1. The Vikings could also put K.J. Osborn in the mix as the No. 3 receiver or add another pass catcher in the coming days as they continue to assemble the roster.