"There are not a lot of people in my shoes that have this opportunity to come from college basketball and play a semester of football," Onobun said. "I think it's a great opportunity. I think it's a blessing. I'm taking it with a grain of salt. I've very excited. I just want to be a sponge and watch the older guys, watch the veterans, and learn everything I can learn so that I can be the best tight end I can possibly be."
Onobun, the son of Nigerian immigrants, played on the Houston Hoops traveling summer team in 2004 with future NFL tight ends Jermichael Finley (Green Bay Packers) and Martellus Bennett (Dallas Cowboys).
But basketball was always Onobun's sport of choice and his path to a college scholarship. His four years with the Wildcats, which included three starts while playing behind future NBA players and having three different head coaches, didn't go as expected, however.
Bennett, his former summer basketball teammate, urged Onobun to give football a try. After graduating from Arizona in four years, Onobun transferred to his hometown Houston, where he would be a graduate student and a walk-on to the Cougars football team.
His one season in Houston included two catches for 33 yards and a touchdown in 11 games and two blocked punts against Southern Miss.
Onobun showed off his athleticism at his pro day, where he ran the 40-yard dash in 4.48 seconds (which would have been the second-best mark by a tight end at the NFL Draft combine) and established himself as a legitimate NFL prospect.
The Rams selected Onobun in the sixth round (170th overall) of April's draft after picking Illinois tight end Michael Hoomanawanui in the fifth round. Onobun was one of the four tight ends the Rams kept on their regular season roster after catching four passes for 64 yards in the preseason.
"I think I've progressed immensely," Onobun said this week. "I think I still have a long way to go, but I also think I've come a long way. I'm definitely better. I'm not exactly where I want to be at the end of the day, but I think I'm a lot better and the coaching staff believes in me enough to where they can call me up to contribute and so do I, so I'm really excited."
Onobun was not active for either of the Rams first two games, but the team is short on tight ends after injuries to Hoomanawanui, Billy Bajema and Daniel Fells and he could be active on Sunday against the Redskins. Onobun and Darcy Johnson, who was cut in training camp but resigned because of the injuries, are the only healthy tight ends on the roster.
"He's being fed some offense right now," Rams coach Steve Spagnuolo said on Thursday. "Now, we'll see when we get to game day what's the best way to go with 45 at what position. So we've still got to make that decision, but in the event that we have him on the 45 we're trying to give him things that he can run."
Rams offensive coordinator Pat Shurmur said: "Fendi had a good week of practice. He's actually competed well through training camp and I feel like he's got the ability to go in there and execute well."
Onobun has prepared this week as if he is going to be active and play in his first NFL game. He's spent extra time after practice working on routes with rookie quarterback Sam Bradford and working on his blocking with offensive linemen.
He knows the injuries to the three other tight ends have opened the door.
"Who wouldn't want to have the opportunity to play on Sundays?" Onobun said. "I think it's a wonderful and great opportunity. I definitely want to take advantage of it. These past two weeks I've been watching the veterans. I've been watching them on game days and seeing how they do things and how they prepare themselves. Now that my number's been called, I'm trying to emulate and do the same thing."