INDIANAPOLIS -- One of the most surprising changes the Indianapolis Colts made for their Week 1 game against the Los Angeles Rams was starting T.J. Green opposite Rashaan Melvin at cornerback.

Green seemed the least likely candidate to start, because it's been less than a month since he made the switch from safety. Rookies Quincy Wilson and Nate Hairston appeared to be the front-runners to replace the injured Vontae Davis (groin) in the starting lineup.

After spending his rookie season at safety, T.J. Green was a surprise starter at cornerback in the Colts' Week 1 loss at the Rams. Jeff Gross/Getty Images

“Nate’s a rookie and had his hands full with the nickel position so we weren’t going to do it with Nate,” coach Chuck Pagano said. “T.J. has been a guy we’ve been working as the third guy, and that was the decision we made a couple weeks ago when Vontae was out because he was going to be the guy.”

Green finished with three tackles -- all solo -- while playing 95 percent (62 of 65) of the Colts' snaps against the Rams, the second-most of defensive player. Los Angeles tested Green from the start, as receiver Robert Woods got past him for a 21-yard gain on the game's third play.

“About what we expected,” Pagano said. “There were going to be some speed bumps having his first start at corner. You see All-Pros struggle that have got a bunch of years under their belt. For the first outing, we figured there would be some plays on there that weren’t so good. But he did some good things as well. He’ll learn and he’ll grow from those.”

This was thought to be a transition season for Green, who's on his third position since entering college. He started out as a receiver then switched to safety while at Clemson. Pagano asked the 2016 second-round draft pick Aug. 16 about making the move to cornerback.

The Colts want to have tall, physical cornerbacks on the outside, and Green, at 6-foot-3 and 211 pounds, fits the mold. He believes he has safety down, and now must continue to work on his technique and instincts at cornerback. With no timetable for Davis' return, Green is looking forward to getting another shot in the starting lineup against the visiting Arizona Cardinals on Sunday. Another area he wants to improve in is being able to “adjust on the fly” when an opponent throws something at him he might not have seen on film.

"He has the right mindset about the position," said veteran Darius Butler, who made the switch from cornerback to safety. "He has the ability or the coaches wouldn’t put him out there. It’s about learning. It’s a whole new world going from safety to corner. Short-term memory is key because you have to have it out on the island. Because of how good these quarterbacks and receivers are, they’re going to win some. You just have to win your share, too."