Year Two of the Mike Zimmer era is unofficially underway as the Vikings begin their offseason workout program at Winter Park today. For now, the workouts are voluntary, and Zimmer and his staff can't actually coach players on the field until a couple of weeks from now.

Running back Adrian Peterson is not expected to show up for the start of the program. He may or may not still be disgruntled, but it's kind of a moot point here. Peterson usually has not participated in the voluntary portion of the offseason program. He was in the house at times a year ago out of respect for Zimmer, showing support to the then-rookie head coach.

The key dates are June 16-18. That's the mandatory minicamp. He can be fined for skipping that.

Peterson also has a $250,000 workout bonus in his contract that he would forfeit by skipping the offseason program. But a league source with access to player contracts told me that Peterson's bonus is tied only to his participation in organized team activities and the mandatory minicamp. So Peterson skipping the start of the offseason program this week would have no bearing financially.

So what exactly might Peterson be missing?

In the first two weeks of the program, known as Phase One, players can work with the strength and conditioning staff and watch film with coaches. Quarterbacks can throw to uncovered receivers.

In two weeks, Phase Two begins and Zimmer and his staff can coach players on the field — with substantial restrictions, though — during that three-week period.

Phase Three is when the Vikings can practice via the OTAs. The June minicamp wraps up the program, then players get a few weeks of vacation time before reporting to Mankato in July.