ANDERSON — Ryan Grigson, the Indianapolis Colts first-year general manager, admits to having more than a few butterflies as the Colts wrap up preparations for the team’s preseason opener with the St. Louis Rams. Grigson, who has spent the last nine years serving in a variety of front-office and scouting positions with the Philadelphia Eagles, will be watching his own team take the field for the first time Sunday afternoon at Lucas Oil Stadium. Hired as the Colts’ general manager on Jan. 11, replacing Bill and Chris Polian, Grigson is one of several new faces in the team's front office and on the coaching staff. “It’s excitement. There’s always the fear of the unknown, so to speak,” he admitted Friday. “I feel confident that, at this point, I know that we’ll come out and play hard. “I have butterflies. I’m not going to lie. We’ve come such a long way in this whole process. To actually see the product on the field against another team, a different color jersey, is exciting. I can’t fake that.” There’s been a near complete culture change in Indianapolis since Grigson took over the reins of the franchise seven months ago. Longtime veterans, such as quarterback Peyton Manning and tight end Dallas Clark, have moved on to Denver and Tampa Bay, respectively. Former head coach Jim Caldwell is now the Baltimore Ravens’ quarterbacks coach. Chuck Pagano, the Ravens’ ex-defensive coordinator, is now the Colts head coach. With Manning moving on, Indianapolis selected former Stanford quarterback Andrew Luck with the first pick in last April’s National Football League draft. And that wasn’t the only change. There are approximately 50 players on the Colts’ training camp roster who weren’t with the team at the end of the 2011 season. Indianapolis owner Jim Irsay gave Grigson the responsibility of rebuilding a franchise that had made 10 straight post-season appearances under Bill Polian’s guidance. The Colts, however, suffered a dramatic slip last year as the team finished with a 2-14 record. That mark tied the Rams for the league’s worst. “I’m not really following anybody’s template [in restructuring the team]. I’m really just kind of keeping it simple. I will always explore anything that makes us better,” Grigson said. “And I think my actions speak to that. We need to keep doing that. Again, my job is to build this team with the help of my staff and the imput of my coaches. And that’s what I intend to do.” The Colts’ revival depends largely on the maturation of Luck, who has been impressive during the first two weeks of training camp. “He really is what we thought he was. We just have to get him in front of some other folks and see how he responds,” Grigson said. “The one thing that you can tell from his body language, from how he reacts on the field, from how he does things, he’s his harshest critic. Nobody is going to able to push his buttons as hard as he pushes his own buttons. That’s evidence that he wants to be great. He wants to make every completion. He wants to complete every pass. And that’s good to see.” The focus now is on this weekend’s game with the Rams. Indianapolis’ first-team offense is tentatively scheduled to be on the field for 20 to 25 plays, although offensive coordinator Bruce Arians has hinted that could change. “I’m so looking towards Sunday, just to see everybody come together and do things. The offensive line. The defensive line. See how they play and see how we do against the run. There’s a lot of little things in the back of my mind,” Grigson said. “I’m looking forward to see. But it’s still brand new. It’s just a blank piece of paper and we’re just filling every line in as we go here day by day.” Redding update -- Defensive end Cory Redding did not practice Friday and will be a game-time decision for Sunday's game with St. Louis. Redding hurt his left elbow during Thursday's workout in Indianapolis. He wore a wrap on the elbow Friday. "Cory is probably right now a game-time decision. His results came back positive on the elbow, so we held him out again [Friday]. We'll wait and see how he feels [today] and then make a game-time decision on him," Pagano said. The coach's designation of positive was a bit confusing, so he elaborated. "Any time there's a plus, when it's a positive, that's good. When that MRI comes back and there's nothing structurally wrong, then it's always positive," he said, reiterating that there was no structural damage to Redding's elbow. Ricardo Mathews, a seventh-round draft pick in 2010, is expected to start in Redding's place Sunday. Chapman, Ijalana -- Grigson offered a few comments Friday on the status of rookie nose tackle Josh Chapman and second-year offensive guard Ben Ijalana. Chapman suffered a knee injury as a senior at Alabama last season but played out the year. He underwent surgery in January and has yet to take part in a practice with the Colts. He was a fifth-round pick in April. “He’s a tough one because he works so hard. He’s so determined, and I don’t think there’s a player in the NFL that is hurting more that he’s not on the field," the general manager said. "This is a true football guy. He’s a true competitor. He works his tail off day in and day out. To me, he’s such a determined guy. He’ll be out there probably sooner than later.” Ijalana, meanwhile, missed most of his rookie season last year with a knee injury. He also underwent two hip surgeries in the offseason. A second-round pick last year, he re-injured the knee during a non-contact drill the first few days of this year's training camp. “Ben was a great athlete. It’s a tremendous loss for the organization. We’re going to get him through this rehab here and hopefully we’re still in the infancy of his whole deal," Grigson said. "But it’s really unfortunate. I talk with him and hope that he maintains a positive attitude and does his rehab. Hopefully he gets back out on the field at some point.” Today's schedule -- The Colts will have a short workout this morning to go over a few last-minute details prior to the St. Louis game, which has been declared a sellout. It will be televised locally and on affiliated stations around the state. "The day before a game, you come in and review everything from [Friday's] practice. Watch the tape and then we'll come out and do a dry run on pre-game routine. We haven't done any of that stuff yet," Pagano explained. "We'll have a walkthrough on that so when we get to stadium [Sunday] it will actually look like we know what we're doing. We'll have a dry run and then we'll do a mock game to run through a lot of situations. The last tune up. And then we'll play [on Sunday]."