Indianapolis — Indianapolis Colts owner Jim Irsay believes rookie quarterback Anthony Richardson may need season-ending surgery on his injured throwing shoulder.

Irsay told ESPN that Richardson and the team's medical staff were still mulling treatment options for Richardson's sprained AC joint but a final decision had not been made — reiterating comments made earlier Monday by coach Shane Steichen.

"The most likelihood is he's probably going to be gone for the year," Irsay said. "I mean, it's not definite but (he) probably misses this year and we're going to have to contend with that factor."

Steichen did not speculate on which route Richardson and the Colts (3-3) would go.

Instead, Steichen said discussions were ongoing as team officials continued to gather information about the injury and all potential treatments, including surgery. Steichen, like Irsay, also acknowledged Richardson's long-term health and the franchise's future would be key factors in the decision-making process.

"Obviously, we want to do what's best for him and this organization moving forward," Steichen said. "Like I said, we'll make that decision when the time is right."

Richardson missed his second game Sunday at Jacksonville, though he traveled with the team and wore a sling to protect his throwing shoulder while watching Indy's loss from the sideline.

He was injured on the end of a short first-half run against Tennessee the previous week. After hitting the ground awkwardly, he stayed down for several minutes before walking slowly to the team's medical tent, his right shoulder drooping. Richardson did not return to that 23-16 victory and went on injured reserve last week, a move that will keep him out at least three more weeks.

The 6-foot-4, 244-pound former Florida star has been injury-prone in his first NFL season.

He missed the final minute of Indy's season opener with a bruised knee and sore ankle, left with a concussion in the first half of a Week 2 victory over Houston, and missed the following week while in the concussion protocol. Then, one week after returning to the field and finishing his first NFL game, he hurt his shoulder.

Indy drafted Richardson with the No. 4 overall pick in April and he was off to a promising start. He had thrown for 577 yards, three TDs and one interception while completing 59.7% of his throws in four games. He also has 25 carries for 136 yards and four TDs, becoming the first quarterback of the Super Bowl era with TD runs in each of his first three NFL games.

Now, his rookie season could be over.

"There's debate going, but it's probably going to lead toward surgery in the next week or so," Irsay said. "We're just trying to figure out exactly how and when and what we want to do and what Anthony wants to do."