After much concern this past weekend over injuries sustained by Brandon Jacobs and LaMichael James, the 49ers looked relatively healthy on Monday afternoon. Here’s a rundown from the first hour of practice, which consists mainly of warmups and position-specific drills (it’s also the only portion of practice that’ll be open to the media for the rest of the season):

— Jacobs arrived at the facility a little after noon, and pulled himself out of the passenger side of his car without putting any weight on his left leg. He then headed to the locker room on crutches.

— James was at practice today, but as an observer. He chatted with Ted Ginn for a bit while both players observed a punt return/coverage drill.

— Aldon Smith was a full participant in team drills. While he wasn’t going at full speed, he also wasn’t limping. He also hit the blocking sled with considerable force.

(Side note: today was actually the first time I’ve seen pro football players hit the blocking sleds from close range, and the impact is rather startling. You’re always aware how much bigger and faster these guys are than average human beings, but the sound that came from the defensive linemen and linebackers hitting the sleds was comparable to that of a minor car collision.)

— At one point Aldon playfully pushed NaVorro Bowman around, both guys laughing. Pretty sure he’ll be fine for the season opener.

— Parys Haralson dropped a couple passes during drills, drawing laughter from a couple of his teammates (including Aldon).

— Delanie Walker looked close to 100% on the far field, running comeback routes and catching passes.

— Perrish Cox warmed up pretty vigorously, then ran sprints along the sideline while the rest of the defensive backs took part in a drill where they worked on intercepting long passes.

— Kourtnei Brown wasn’t in pads, but took part in early drills with the rest of the linebackers (he didn’t hit the sleds).

— Neither Cam Johnson nor Chris Culliver were in the house.

— One observation on a guy whose injury was a major focus a week ago … Michael Crabtree looks noticeably bigger this year, particularly in the upper body. Perhaps he took Jerry Rice’s advice/criticism to heart?

— Also, Crabtree was warming up with the defensive lineman for some reason.

— At the beginning of practice, Harbaugh mugged for the cameras while standing with the officials who help out during Niners practices (I missed the part where he posed with the refs, grinning from ear to ear). After a poorly-officiated game on Saturday night, I guess Harbaugh wanted to let bygones be bygones.