Since arriving in Oakland in 2014, Donald Penn has been one of the NFL's best offensive tackles. He ranked 10th or better in his first three seasons, according to Pro Football Focus' grades, and last season he was 21st.

Penn was understandably upset when the Raiders used the 15th pick in the 2018 NFL Draft to take tackle Kolton Miller. He was so upset, in fact, that he got new (old) coach Jon Gruden on the phone to talk about it.

"I'm not going to lie, as soon as I saw the draft pick, I called Gruden immediately. Like 'man, what the f---?,'" Penn said during an appearance on Michael Rapoport's podcast, via "He didn't answer, but when I saw him the next Monday, he was joking with me saying, 'You were ready to kick my ass, huh, Donald?! You were mad as a mother------!'"

Gruden has maintained that drafting Miller had nothing to do with Penn.

"Donald has been a very good player for the Raiders, a guy that I coached in Tampa, know extremely well, but this has nothing to do with Donald Penn," Gruden said after Miller was selected. "This is about the future of the Oakland Raiders, we have an outstanding young quarterback, we have a need at the position, and we're very fortunate to address it, but it doesn't really say anything to Donald Penn."

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The 35-year-old is entering his 13th season and remains an integral part of the Raiders' offensive line. But Miller -- and offensive tackle Brandon Parker, who the Raiders took in the third round this year -- gives the unit youth and depth. Penn understands this.

"I'm going to try and get those young guys right and take them under my wing," he said. "... So when I am done, I want to make sure this first-round pick gets all my tips, everything I got in my back pocket. So when he does get in there, he can protect my guy DC like I do. Because at the end of the day, me and DC are always going to be friends."

The Raiders are coming off a forgettable six-win campaign that cost Jack Del Rio his job. Now it's up to Gruden, who coached the team from 1998-2001 but had been out of the NFL since 2009, to get Oakland back to the playoffs, where they have made exactly one appearance (in 2016) since 2003.