Chuck Pagano has described Daniel Adongo's development since signing for the Indianapolis Colts as "amazing".
The Kenyan, who has played club rugby in South Africa and New Zealand, signed for the AFC South side last month, despite having no prior experience of American football.
The head coach told reporters: "It's amazing what everybody has done with this kid. He's picked up the system and the scheme and the nuances of the game. He's still learning obviously.
"He's a quick study. He's growing every day, guy is like a sponge. Every time you turn around, he's asking somebody a question. So, he's doing well. I turn around and he's standing right behind me the whole game waiting to get thrown out there.
"I'm just going to protect Daniel from himself. Guys have been playing five, six, seven years in the league running down on a kickoff and don't see a trap block coming. I just don't want to throw him into a situation like that right now where he doesn't have a full grasp of everything going on."
The 23-year-old linebacker has previously played for Kenya's Under-18 and Under-21 national teams.
