Mike McCarthy doesn’t need anyone to tell him how good his offense looks on paper. He just needs the unit to clean up its act on the field.

McCarthy didn’t like what he saw in Monday night’s practice, which was moved inside the Don Hutson Center due to rainy weather. The offense fumbled three times during 11-on-11 work and committed a few false starts to boot, disappointing a coach who was hoping for a much sharper effort following an abbreviated “Family Night” on Saturday and a day off on Sunday.

“The ball on the ground, that’s unacceptable,” McCarthy said. “That was not a very good practice at all for the offense, just from a fundamental standpoint. You have some tough looks, especially from our defense. That’s installation football. But I did not like the fundamentals, particularly the ball security of the offense tonight. It was poor.”

The Packers didn’t lose a fumble by a running back all last season, in 20 games including the playoffs, but they looked nothing like that sure-handed bunch on Monday.

Problems surfaced in an early team period, as quarterback Aaron Rodgers and running back James Starks fumbled an exchange when they bumped into each other. Then, in a later team period, with the offense backed up near its own goal line, running back Ryan Grant coughed one up as he tried to break through the line, with safety Nick Collins scooping it up on the run.

Just a few more snaps went by before Starks and backup quarterback Matt Flynn dropped an exchange, which prompted the coaches to insert rookie Alex Green and backup Dimitri Nance at running back for the next several snaps. It’s worth noting, however, that Green wasn’t immune to fumbleitis, either. During the ball-security drill at the beginning of practice, when the coaches dump a ball in a bucket of water and then hand it to an offensive skill player while two defensive players try to strip it, Green lost the handle on one thanks to cornerback Sam Shields.

“We look great on paper, there’s no doubt about it, but we’re not close to where we need to be as a football team,” McCarthy said. “We realize that. We have a lot of work to do. I’m not going to throw out any bouquets tonight. We need to step it up in the area of fundamentals.”

With just three more practices before the preseason opener on Saturday in Cleveland, McCarthy recognizes that time is of the essence.

“It’s important for everybody to mentally tighten it down,” he said. “We have more mental errors this year than in the past. That’s probably true around the league, but I don’t really care about the league. We have a standard here. We’re pushing to get to that standard, and I’m fully confident we’ll get there.

“But you have to take care of the football on offense. Pre-snap penalties and don’t take care of the football, that’s a bad day.”

Other observations from Monday’s workout:

  • Frank Zombo was back with the first-team defense at outside linebacker in the rotation that is continuing with Erik Walden and Brad Jones.

  • Rodgers continues to work the tight ends into the offense, as he always has. He opened one team period with a quick-release bullet to Jermichael Finley over the middle off play-action, but a similar play to the end zone failed to connect as the ball glanced off Finley’s outstretched hands. Later, Rodgers threaded a tight throw for an impressive completion to rookie D.J. Williams, who was blanketed by linebacker Desmond Bishop.

  • Cornerback Charles Woodson showed he can still stay with the elite receivers when he hung with Greg Jennings on a deep corner route and dived to knock the ball away with a textbook deflection.

  • The quarterbacks were taking turns trying to loft 20-yard passes into an elevated hoop in the corner of the end zone, and Flynn got the ball into the hoop twice. Third-string QB Graham Harrell also got one in.

  • Shields made one of his most notable plays in camp during seven-on-seven, as a Rodgers pass intended for Jordy Nelson in the back of the end zone was deflected. Shields got his hands on it and gained control of it while tip-toeing the end line to get both feet in bounds for the interception.

Injury update: Two players dropped out of practice on Monday with injuries. Offensive lineman Marshall Newhouse, who was off to a strong start at left tackle, sprained his shoulder, while receiver Brett Swain injured his hamstring.

Kicker Mason Crosby has a sprained ankle and did not kick. McCarthy said he’s “hopeful” Crosby will be ready for the Cleveland game.

Cornerback Brandon Underwood sprained his knee on Saturday night and will be out a couple of weeks.

Also new to the injury list and not practicing were linebacker Cardia Jackson and tackle Chris Campbell. McCarthy was not asked about their injuries.

Continuing to sit out were cornerback Davon House (hamstring), linebacker Diyral Briggs (hamstring), guard Adrian Battles (Achilles) and defensive end Eli Joseph (hamstring).

Returning to practice on Monday from injury were cornerback Tramon Williams (hip), linebacker Clay Matthews (glute), tight end Tom Crabtree (hip flexor), receiver Greg Jennings (hip flexor) and defensive end Lawrence Guy (concussion).