If you've followed James Casey's career since he stepped on the field at Rice, you're the least surprised person on earth by what happened Sunday afternoon at Reliant Stadium.

You may have been sorry to see fullback Vonta Leach sign with the Ravens. You appreciated his toughness and the relentless battering-ram style that opened plenty of holes for Arian Foster. You also liked what he gave the Texans in terms of personality and leadership.

Yet you still felt pretty good about things. You knew James Casey didn't look like a prototype fullback and that there might be a period of adjustment. You also knew that Casey, ever the perfectionist, would end up doing a terrific job and that he also would give the coaches options other players couldn't.

That's one of the advantages of having smart guys. Coaches can throw a lot at them, knowing they'll grasp all of it, seldom make a mental mistake and maximize their abilities.

At Rice, Casey did amazing things, playing here, there and everywhere. In 2008, his final season, he carried the ball 57 times as a running back, caught 111 passes as a tight end and threw two touchdown passes as a quarterback. For good measure, he also returned 14 punts.

He scored 19 touchdowns that year, and if he'd stayed another season, he would have been Rice's starting quarterback in 2009. But he'd spent four years in minor league baseball, and as much as he loved Rice, it was time to find out if he could make it in the NFL.

Leap of faith rewarded

(Last spring, he returned to Rice and finished his degree - a triple major in economics, managerial studies and sports management with a 3.67 GPA.)

The Texans took him in the fifth round of the 2009 draft, and in his first two seasons, he played only sparingly, starting five games at tight end and catching 11 passes.

He was on the field so little that it was difficult for the Texans to know what they had, or if he was capable of playing fullback. And they did attempt to re-sign Leach. They also brought in veteran fullback Lawrence Vickers, which wasn't exactly a vote of confidence in Casey.

And then in the season opener, Casey did pretty much what you'd seen him do at Rice. He started at fullback and appeared to do a solid job blocking. On one particular play, he turned the corner and flattened a linebacker.

There were other times when he showed his versatility by lining up at fullback, then shifting to wide receiver. He has the size and strength to block inside but the speed to run pass routes outside. In other words, he's an interesting weapon on an offense loaded with them.

Opening up playbook

"It gives us a lot of options because we can run various offenses," coach Gary Kubiak said. "James has not only turned into a fine player each and every time out, but his football IQ helps us as a football team, allows us to do a lot of things."

Casey caught three passes Sunday against the Colts, two of them for first downs. His real contribution was helping the running game.

"I think he did a great job," Texans offensive coordinator Rick Dennison said. "He just keeps working on his technique, gets better every day. He did some really good things for us. He's another weapon.''

As for Casey, he seemed to take the whole thing in stride. About the only time he seemed stressed during training camp was when reporters asked questions that seemed to imply doubt about his ability to make the switch from tight end to fullback.

"I think I did really well," he said. "I had some good (plays), had some bad ones of course. Good thing was I got a lot of work because we were up."

With the Texans leading by 34 points at halftime, they became a run-first team in the second half and allowed Casey to polish his technique at fullback.

His playing time will vary depending on how much Kubiak uses a fullback. However, with Foster probably back in the lineup Sunday, he could have a busy day. And you already know he'll do fine.

richard.justice@chron.com twitter.com/richardjustice