WESTFIELD — Adonai Mitchell took his first snaps in the slot during Friday’s practice, and the results were encouraging.

The Indianapolis Colts rookie had three catches on three targets with the first-team offense as head coach Shane Steichen tests ways to replace injured wide receiver Josh Downs.

Steichen confirmed Downs suffered a high ankle sprain during Wednesday’s practice but declined to set a timeline for the second-year standout’s recovery. The conventional rehab period is four to six weeks.

Indianapolis is slated to open the regular season Sept. 8 against the Houston Texans at Lucas Oil Stadium, and the first two weeks of the regular season could fall inside Downs’ recovery time.

It’s clear Mitchell is among the options to get snaps in Downs’ stead, but it’s equally clear the promising rookie is not alone.

“I think the slot position — obviously, there’s certain body types, but you can put anybody in the slot,” Steichen said. “It’s all about what route concept you’re running and where you want certain guys. I mean, those guys are all interchangeable.

“I mean, that’ll happen throughout the year. We’ll move guys inside, outside. You’ll see guys all over the place.”

It was a good day for the receiving corps as a whole in the first full practice since Downs was injured.

Quarterback Anthony Richardson was 14-of-17 with three touchdowns in 11-on-11 drills, and Michael Pittman Jr. was his favorite target with five receptions and one score.

Alec Pierce — who has been competing with Mitchell for the No. 3 receiver role — also had a very strong day. He caught three passes and one touchdown during full-team drills and had a second leaping touchdown reception during the seven-on-seven period.

It was more evidence of the depth in the position group, which has also been without veteran Ashton Dulin (hamstring) for the past two practices.

“Everybody’s been having some time in the offense,” Richardson said. “Now everybody trusts each other. Everybody trusts the game plan that Coach Shane puts together for us. So everybody’s relying on their instincts and their playmaking ability just to go out there and just have fun and enjoy it. So we’ve just all been locked in.”

GAME TIME

The preseason begins Sunday with a 1 p.m. kickoff against the Denver Broncos at Lucas Oil Stadium.

Steichen said most starters will play one or two series in the game, though a few could be held out all together.

The Colts will play three preseason games and hold three joint practices over the next two weeks.

“They’re going to be huge,” Steichen said. “I mean, we’ve been going against each other now for what is it — two-and-a-half, three weeks — and to go against somebody else this Sunday and then next week versus Arizona for two days will be huge for our guys.

“Then going to Cincinnati will be huge, and just keep attacking every day. I mean, the guys are working their tails off. It gets closer and closer every day. I know the guys are excited for that.”

INJURY REPORT

Downs, Dulin, cornerback JuJu Brents (rest), linebaker Jaylon Carlies (hip), defensive end Genard Avery (undisclosed) and defensive tackle DeForest Buckner (rest) did not participate in Friday’s 60-minute session.

Safety Kendell Brooks, linebacker Liam Anderson, tight end Will Mallory and defensive end Tyquan Lewis returned to practice Friday.

NEXT PRACTICE

The Arizona Cardinals will be in town Wednesday for the first of two joint practices on “Fan Appreciation” day.

Practice is scheduled to run from 6 to 8 p.m., and Colts City will be open from 4 to 8 p.m.

Tickets are $5 for fans 18 and over and must be downloaded at Colts.com/camp. Fans under 18 will be admitted free.