When S Dashon Goldson intercepted QB Alex Smith on a tipped ball during the final phase of practice Friday, coach Jim Harbaugh had seen enough. He blew his whistle and called for the end of practice -- earlier than expected.

It was a day dominated by the defense, and Goldon’s pick during the offense’s two-minute drill was a fitting end. If one thing is clear a week into training camp, it’s that the team’s defense is at a more advanced stage than the offense.

“Lopsided the last couple of days,” Smith said. “New phase of camp for us in the sense that, kind of going first, second and third down and all of the sudden the last two days were red zone and red zone emphasis. First two days of it and not good. The defense definitely got the better of us, I felt like, in all aspects, 7-on-7 and team.”

Harbaugh praised the defense, and said the offense was dominated “about every which way it could be.”

It shouldn’t come as much of a surprise. It’s generally easier for a defense to get up to speed early in camp and the 49ers unit is at even more of an advantage because it returns all its starters from last year, when it ranked No. 2 in the NFL in scoring defense and No. 4 in overall defense.

Smith and WR Kyle Williams complimented the defense, but neither wanted to make excuses.

“We want to get out there and compete and make plays,” Williams said. “We feel like if we can do that on a daily basis out here, we’ll be in a good spot to do that against the rest of the league.”

Iupati misses practice for birth of first child: LG Mike Iupati missed practice Friday as his wife, Ashley, was set to deliver the couple’s first child. “Real excited about that," Harbaugh said. “Our team’s about to get stronger. Wish Mike and Ashley the best and our prayers are with them.”

Looney suits up: Rookie G Joe Looney was a full participant in practice for the first time in his career. The fourth-round pick out of Vanderbilt passed his physical this week after rehabbing from a foot injury, which he suffered in the Senior Bowl.  “He got action in there at guard, and some good,” Harbaugh said. “It’s good to have him back on the field, good to have him back started. I think we’ll have a lot to work with there.”

Crabtree returning soon?: After sitting out Friday, WR Michael Crabtree has missed a week’s worth of practices with what is believed to be a calf injury. The timetable for his return remains unclear, but Harbaugh didn’t sound concerned about the team’s leading receiver from last year. “We feel like we’ll get him back soon and we can pick right up,” Harbaugh said. “I don’t think this is going to be a major bump in the road. I think it’s going to be a minor one. He’s champing at the bit to get back out there, and anticipate that happening soon.”

Hastings, Holcomb, Byham out: WR Joe Hastings (hamstring), (leg) CB Curtis Holcomb and Nate Byham (unknown) missed practice Friday. Byham said Thursday his surgically repaired knee is sore, but it had not been affecting his play.

Jenkins among punt returners: First-round pick A.J. Jenkins joined Ted Ginn Jr., LaMichael James and Kyle Williams in the team’s rotation at PR. Jenkins did not return a punt during his four-year at Illinois and it showed at times Friday. While Ginn, James and Williams made catching the punts look routine, Jenkins struggled. He returned 22 kickoffs in his senior year for the Illini, including a 96-yard TD against Indiana.

Follow 49ers reporter Kyle Bonagura on Twitter: @CBSSportsNFLSF and @KyleBonagura.