At first, Trevor Siemian downplayed it as “optional surgery.”

His left shoulder, injured in a week 4 win at Tampa Bay during the 2016 season, was still giving him trouble as he tried to lift weights in late-December.

Get it repaired, no big whip.

But then his orthopedic surgeon, Dr. Neal ElAttrache, discovered more damage than originally thought while executing the procedure on Jan. 5 in Los Angeles.

Instead of a grade 3 separation in the AC joint of Siemian’s non-throwing shoulder, Dr. ElAttrache saw ligaments torn in the areas where the clavicle, scapula and AC joint connect. A more severe grade 5 separation was diagnosed. This was not “optional” surgery. The operation was required.

When the surgery was finished, a four to six-month recovery period was given.

“Whether it was grade 3 or grade 4 or grade 5, to me it was irrelevant because the season was over,’’ Siemian said in a phone conversation Tuesday in his typical understated manner. “This is the offseason and regardless of what the extent was, it’s going to be good to go.’’

It has been speculated that the more severe injury would cause Siemian to miss most of the Broncos’ offseason workouts. Not so, he said.

“We’re still on track to be full go for the start of OTAs,’’ Siemian said. “That’s the plan. The four to six months thing is really more for contact. Unless coach (Vance) Joseph is going to change the rules and have us work on the quarterback slide, I think I’ll be OK.’’

Siemian will be limited when the Broncos begin their offseason conditioning program in April. But the more important organized team activities (OTAs) – when the offense is allowed to line up against the defense and run live plays -- don’t begin until late-May. That’s close to five months post-Siemian’s surgery. There is no contact during OTAS, at least not during plays involving the so called “skilled positions.’’

“If I was an offensive lineman and had to block, I’d probably have problems,’’ said Siemian, who is back in his hometown of Orlando rehabbing. “But I should be able to make all my throws.’’

What the more significant grade 5 separation does show is Siemian was playing the bulk of last season with a more serious injury than people realized. He missed just one game with shoulder separation, and later missed one more because of a midfoot sprain in his left foot. He still managed to post an 8-6 record in his first NFL season of playing, completing 59.5 percent of his passes for 3,401 yards and 18 touchdowns against 10 interceptions.

As it stands now, Siemian and Paxton Lynch, the Broncos’ first-round draft pick last year, will compete for the starting quarterback job this offseason. Siemian says he will be ready to fully compete.