The club also acquired veteran free agent help in linebacker Ernie Sims and defensive end Jamaal Anderson. Anderson and Sims watched the session and should join practices soon.
The rookie offensive tackle was immersed immediately in work on the field as Indianapolis held its fourth training camp practice. Castonzo worked with a few veterans and younger players in his first action with the team.
Wednesday, Castonzo worked in the morning practice for the second time. He was happy to join the action with the Colts.
"It's a great opportunity. I'm just looking forward to taking advantage of that opportunity and putting everything I've got out there and doing a good job," said Castonzo. "I had an opportunity to get down here a little bit in the summer and was able to hit the ground running. My brain isn't about to explode, I'm just trying to get all the techniques down and really get everything hammered in so that it's natural for me."
Castonzo kept the mindset through the spring that he wanted to be the club's starter at left tackle from the outset of his career. He has not changed his target.
"I definitely want to be the starting left tackle," said Castonzo. "They're going to throw it all at me and expect me to get the job done. I expect that of myself, too."
Head Coach Jim Caldwell welcomed the addition of Castonzo, and he knows the Boston College product will need to learn on the run.
"He's going to have to be a fast learner, but he is, too. He's a smart guy who I think will catch on rather quickly," said Caldwell. "The big thing is, you have to be able get out there on the field and have a chance to see Dwight (Freeney) and Robert (Mathis) rush the passer (and) try to pass protect against those guys. We have probably the best situation for a young guy. He's going to see two guys who know how to throw the fastball. He will get a lot of work."
In the early stages of camp, the line is working without a few veterans and those who are practicing are helping the newer players.
"We're going to have to re-work a few things within our offensive line," said Caldwell. "Thank goodness we do have a number of veterans who are in there. It will help sort of calm the nerves of some of the youngsters who will have to play for us. We have some young guys who are going to have to learn fast in the next couple of weeks."
Offensive tackle Ryan Diem is one of the veterans not practicing at the moment because of CBA (Collective Bargaining Agreement) rules. Diem is in his 11th year with the club. He remembers well the atmosphere a rookie lineman is entering. He knows Castonzo and second-round pick offensive guard Ben Ijalana will be adapting to the culture of the team and while it will be a learning experience, it is one many linemen have gone through in Indianapolis and have succeeded.
"That first couple of days you come in, you're just lost. You don't know where the meeting rooms are," said Diem. "They're going to come in and we're going to help get them up to speed. That's how it was when I came in. We had Adam Meadows and Tarik Glenn and Waverly Jackson and Larry Moore and Jeff Saturday and those guys. They (the club's veterans) help get you up to speed and get you on the right path and teach you how to work."
Castonzo set the school record with 54 career starts. He opened his final three seasons at left tackle after starting 14 games on the right side as a freshman. Castonzo started 13 games as a senior team captain, and was a Third-Team All-American by Associated Press and an All-ACC First-Team pick.
Sims is a sixth-year NFL veteran who spent four seasons with Detroit (2006-09) and the 2010 season with Philadelphia. In 74 career contests, he had 475 tackles (329 solo), 4.5 sacks, one interception, 10 passes defensed, five forced fumble and three fumble recoveries. He was a 16-game starter his first three seasons and had a career-high 134 tackles in 2007.
"I'm excited that I am back in a Tampa Two defense," he said. "It's a true blessing to be in Indianapolis. It is an opportunity the Lord opened up that I can step in and make plays with this defense. I'm extremely happy."
Anderson was the eighth overall selection by Atlanta in the 2007 draft. He started 47 of 60 games in four seasons. Anderson had 4.5 sacks, nine passes defensed and two forced fumbles.
"Honestly, I haven't figured out the exact role yet," said Anderson. "I guess I will find out more when I'm practicing. I have some great defensive ends in front of me. I have a great coach, a great scheme, and I can't wait to get out there and learn. I am here with a fresh start. Obviously, they see something in me, and that's why I am here."
Indianapolis has a reputation for using the veteran free agent market on a very limited basis. When it does take the route, Caldwell explained what the club pursues.
"You're looking for someone who can help your team at whatever position," said Caldwell. "It's not just necessarily just for depth, but it's also (for) a guy who can come in and have an impact. We're looking for guys who have been around, who have a proven track record and fits within the context of what we do. He has to fit our system from a schematic standpoint, also philosophically as well. We take all those things into account when we're looking for someone to come in from the free agent market."