Williams’ comments came in response to an article written by former Port Adelaide player Josh Francou, which called for Thomson to follow the lead of now-Crow Brad Symes and chase better opportunities elsewhere.
The 21-year-old has played 25 games with the Power since his 2005 debut, including four this season.
The Sturt junior starred in the round five win over West Coast with 21 touches and two goals, but was left out of the side to play St Kilda in round 10.
Thomson dominated in the SANFL last weekend with 20-plus touches and four goals to half time.
On Friday, Williams reaffirmed Thomson was a required player at the club and revealed that the former first round draft pick was battling osteitis pubis.
"It’s tough for people outside the club to know, but Adam has been rested in regard to OP [osteitis pubis]," Williams said.
"It’s easy to write an article like that, but we’ve valued Adam’s input into our side this year, much more than any other year, to the point where we didn’t actually drop him. We gave him time off.
"He played really well in the first half last week, without any doubt, and we would like to think that he needs to get a little bit more time on the track and in the game to give him another opportunity to get back in the [senior] team.
"No way known [will we let him leave]."
Williams was also quizzed on the future of key position player Damon White, who appears set to miss out on selection this week despite the injury to fellow tall Toby Thurstans.
White has been stranded on 49 games since round 19 last season and actually sought a trade to leave Port Adelaide late last year.
"It’s difficult for Damon. It was his choice to go last year and, the truth be known, no-one picked him up or wanted to trade for him. It’s not like we tried to stop him. He knew it was going to be difficult for the year," Williams said.
"He’s been waiting for opportunities in regards to the forwards and the backs and as soon as Toby’s out we ask, ‘Do we put him in or not?’ and that’s a question we ask when we look at the Geelong match-ups as well.
"We’re delighted that he played on Ian Perrie last week and, in a game where his team got smashed, I think Perrie only kicked the last goal of the game.
"He’s showing good versatility and if he doesn’t play this week, it doesn’t mean to say he won’t play [next] week."
