San Francisco 49ers receiver Deebo Samuel played 60 snaps against the Tampa Bay Buccaneers last week, and head coach Kyle Shanahan says he would like to see that number come down.

"I think he learned what the NFL is like," Shanahan told reporters of Samuel on Wednesday. "I think it was our fault for playing him too much. That's sort of what I was talking about earlier. We should've had Dante [Pettis] in for more and taken those reps down a little bit, but that's the standard in this league and how hard you have to go and how every play matters."

Pettis, who re-aggravated a groin injury earlier in the week, was limited to just two snaps and had one reception for seven yards. Samuel had three receptions for 17 yards, but also committed a pair of costly mistakes: A false start that killed what could have been a big play and a fumble that occurred while the 49ers were in field goal range.

"The false start was huge, just because it was going to him and had a very good chance to be an explosive play, just like the one we just missed to [Kendrick] Bourne the series before that," Shanahan said. "And then the fumble cost us three points. Just in the little plays, the ones that people wouldn't notice, but just down in and down out. It happens with all receivers."

Samuel said he didn't know he would receive so much playing time going into the game, and that nerves played a role in his performance.

"Kind of more anxious than anything," the rookie receiver said, per NBC Sports Bay Area. "You know, it was kind of first-game rookie jitters. You hear the play call and kind of figure it's coming to you and you're ready to make the play, but rather than being locked in, I was jumping offsides."

MORE 49ERS: 49ers rookie Nick Bosa misses practice with sore ankle

On Monday, Shanahan said to expect more reps for Pettis, who currently plays the same receiver position (X) as Deebo Samuel.

"It's definitely not Deebo's job," Shanahan said. "It's not anyone's right now. That's something that I kind of talked about all preseason. No one's really taken that role... I definitely didn't plan on Dante getting only two reps. He should have been in more than that. That starts with me. I'll make sure not to let that happen again."

Eric Ting is an SFGATE staff writer. Email: eric.ting@sfgate.com | Twitter:@_ericting