The Oakland Raiders officially kicked off Phase Three of the Offseason Workout Program this week, holding the first three of their 10 allotted Organized Team Activities [OTAs]. The Silver and Black's final seven OTAs will be held over the next few weeks, and the Offseason Workout Program will officially wrap up June 15 at the conclusion of the team's three-day, Mandatory Minicamp.

A lot has happened this week during the first three OTAs, so let's catch you up on anything you might have missed.

"Megatron" makes an appearance

The Oakland Raiders added yet another talented wide receiver to the mix this week, even though he won't be strapping a helmet on and going to work.

All-Pro, and likely future Hall of Famer, wide receiver Calvin Johnson took up residence at 1220 Harbor Bay Parkway for the week, observing practice as a guest of offensive coordinator Todd Downing.

Not surprisingly, Johnson spent some time chatting with the Raiders receivers during his visit, and following Tuesday's OTA, Amari Cooper talked about what it was like to have "Megatron" in the house.

Head Coach Jack Del Rio and others take to the podium

After the Silver and Black wrapped up Tuesday's on-field session, Head Coach Del Rio took to the podium, discussing a wide array of topics, ranging from the addition of running back Marshawn Lynch, to the production of some of the team's draft picks.

After Del Rio took the podium, Cooper, along with tackle Donald Penn, and defensive end Mario Edwards Jr. had their time behind the microphone as well.

The Raiders sound off on the field

Take a look at the practice videos from the Raiders three OTAs this week.

Smile, you're on camera

Here are some of the best images from the first week of OTAs.