The hustle and bustle is back at the Under Armour Performance Center.

After taking some time away from the game over the last few months, the players returned to work early Monday morning for the start of the team's voluntary conditioning program.

"If you don't like being around when the players come back, you're in the wrong business," Ravens Head Coach John Harbaugh said. "This is what we do. This is football, man. When the football players come back in the building, everybody should be excited about that."

The offseason program is broken up into three phases, with Phase One lasting two weeks. The activities during this time are limited to strength and conditioning, physical rehabilitation and classroom work.

Coaches are not allowed to lead the players through on-field workouts during this period of the offseason, and the NFL's Collective Bargaining Agreements limits the time that the players are allowed in the building.

The conditioning program is voluntary, but the Ravens have a history of strong participation from key players and veteran leaders. 

"We fully expect our guys to be in shape when they walk in the door," Harbaugh said. "And if they're not in shape, they're going to have to work extra hard to get caught up. Most of our guys, if not all of our guys, are already going to be in phenomenal shape."

Phase Two of the offseason begins May 4 and lasts for three weeks. Coaching involvement ramps up during this time, as the coaches are able to conduct some on-field instruction like individual drills. No 11-on-11 drills are permitted at this point.

Phase Three begins May 25, and it includes the 10-day period of Organized Team Activities (OTAs).

Minicamp, the only mandatory portion of the offseason program, will take place from June 16-18.