As players and coaches geared up for the Ravens and 49ers preseason opener at M&T Bank Stadium Thursday night, the Under Armour Performance Center was buzzing without them.

Final preparations were being made for what comes after the game – three days of practice with two teams under one roof.

Talk about cramped.

The Ravens are hosting the 49ers, who will practice, eat, study and do all other normal football activities side-by-side from Saturday through Monday. And with that comes a lot of preparation.

"We have an army of folks here doing a great job, led by [Ravens Vice President of Operations] Bob Eller," Head Coach John Harbaugh said.

"[Ravens President] Dick Cass has really spared no expense to try to do this right, and we want to be good hosts. The 49ers are coming all the way across the country, and we want to be good hosts and make the most of it."

The Ravens are hosting a lot of people. There are 90 San Francisco players, plus another 60 or so staff members. That means just about every nook and cranny of the Under Armour Performance Center will be put to use.

Here are a few of the changes around the building:

Some of the Ravens position group meeting rooms will stay in place. Others will be relocated on the second floor to make room for 49ers meeting rooms downstairs.

Ravens running backs and linebackers will move to have meetings in their position coaches' offices upstairs. The offensive linemen will be in the main business conference room, circled around a huge table with comfy chairs they'll surely appreciate. Other Ravens position groups will hold their meetings in scouting offices.

The 49ers main team meeting room is in the basketball court. Their offensive line meeting room will be in one racquetball court. The running backs will be in the other.

The cafeteria will be shared. There are as many tables and chairs as humanly possible jammed into the room and an air-conditioned tent has been erected in the adjoining patio. A 49ers and Ravens helmet each sit atop the salad bar.

The 49ers will be mostly stationed in the indoor practice field. Their player looker room, staff locker room, equipment room training room, staff locker room and lounge area are partitioned off by tall scarlet, gold and black curtains. It's like their own village with signs pointing everywhere.

There are three outdoor fields to accommodate the two teams at the same time. The 49ers will have one, with their logo painted in each end zone. The Ravens will have another. The third field is where the two teams will scrimmage each other, with each team's logo in opposite end zones.

Harbaugh was jokingly asked if he'll hear about potential problems from the 49ers. Those complaints would presumably come from little brother Jim. The two brothers may watch practice tape together in Harbaugh's office, perhaps with their father Jack.

"I might," Harbaugh said with a smile. "I might hear about it, yes."