KANSAS CITY, Mo. — The Rams shocked fans — and much of the NFL — when they selected quarterback Ty Simpson with the 13th pick in the NFL draft.

Simpson started only 15 games at Alabama before the Rams ostensibly made him the eventual heir apparent to Matthew Stafford.

Now, after offseason workouts, two weeks of training camp and a few preseason practices, Simpson will get his first NFL game opportunity when the Rams open the preseason against Kansas City Chiefs at Arrowhead Stadium on Saturday at 1 p.m. PDT (CBS).

Fourth-year pro Stetson Bennett will start, but Simpson will play in the game.

“I’m really ready to show who I am,” Simpson said this week.

Simpson, 23, acknowledges the pressure that comes with his draft position, especially for a team that is favored to win Super Bowl LXI. But he does not feel it.

Not outwardly, anyway.

“I try to be as present as I can, and make sure every day I understand how much of a blessing it is knowing that I am the No. 13 pick and everything that comes with it,” Simpson said during training camp. “But also understanding that being here every day, and making the most out of every opportunity that I get, is everything I can ask for.”

Simpson started slow in the first few training camp workouts, but he appeared to break through when he stepped up in the pocket and completed a pass across the middle of the field. Simpson said he had begun to “put the puzzle pieces together,” marrying concepts with lessons learned watching Stafford and Bennett.

Star receiver Puka Nacua noticed.

“His arm and the confidence that he’s throwing the ball with has definitely grown a ton,” since offseason workouts, Nacua said before the Rams broke camp. “I think he’s feeling more comfortable in the pocket, understanding and seeing more guys run routes.”

Said offensive coordinator Nate Scheelhaase: “You’ve certainly seen him go and make some throws and go and compete in a really cool way.”

During this week’s joint workout with the Dallas Cowboys, Simpson played a few series, and completed a touchdown pass during a red-zone period.

But there is no tackling during practices. So Saturday will be Simpson’s first time experiencing NFL contact.

“It’s going to be a whole different lifestyle,” he quipped.

Rams quarterback Ty Simpson looks to pass during a drill in training camp at Loyola Marymount on July 27.

Rams quarterback Ty Simpson looks to pass during a drill in training camp at Loyola Marymount on July 27.

(Eric Thayer / Los Angeles Times)

Coach Sean McVay does not play starters or other projected significant contributors during the preseason. In addition to Nacua and Davante Adams being held out, receivers Jordan Whittington and Konata Mumpfield also will not play, McVay said.

Simpson’s fellow rookies — tight end Max Klare, offensive lineman Keagan Trost, receiver CJ Daniels and defensive lineman Tim Keenan — will play.

Scheelhaase will call plays.

This will be Bennett’s seventh — and most important — preseason start.

Jimmy Garoppolo is no longer on the roster and Stafford was on a limited schedule during training camp, so Bennett worked with the first-team offense for the first time in his career. The former Georgia star, who led the Bulldogs to two national titles, played with confidence and made plays in his bid to show McVay and teammates that he can step in if Stafford is sidelined during the season.

McVay is looking to see how Bennett and Simpson manage the offense before and after the snap. He anticipates that both will use their mobility to make plays if the pocket collapses.

“Seeing some of that stuff come to life will be important,” McVay said. “But I think it’s got to occur naturally.”

Stafford, Bennett and quarterbacks coach Dave Ragone are among those who have eased Simpson’s transition to the NFL. As Simpson prepared for Saturday’s game, Stafford offered counsel.

“The best advice he gave me was, ‘Just go let it rip. It’s nothing that you haven’t done before,’” Simpson said.

But this will be the first time Simpson will do it as a pro.

Simpson anticipates that it will be “surreal” to put on his game jersey and fulfill a dream of playing in the NFL.

“There are going to be things that I mess up on,” he said. “I’m going to learn from them and move on, and next week be able to learn from it and make sure it doesn’t happen again.”