49ers training camp takeaways: Rookie Mustapha makes Day 1 splash

SANTA CLARA — The 49ers officially opened training camp on Wednesday with two of their top offensive players skipping the first practice of the summer. One is a hold out. The other is a hold in. The 49ers went through an hour-long, non-padded practice. And most of the attention was on who was not in attendance rather than the other star players who suited up for the workout. And that's how we begin the top five takeaways from Day 1 of 49ers training camp: Williams is a no-show Is All-Pro left tackle Trent Williams underpaid? He believes so, and the two sides are working toward a resolution. Coach Kyle Shanahan disclosed that Williams' absence from training camp is contract-related. General manager John Lynch and Williams' agent are in negotiations aimed at settling the issue, Shanahan said. Williams is subject to $50,000 in fines for each day he does not report to camp. Williams' contract calls for him to make $20 million this season in base salary with another $750,000 available per-game roster bonuses. He is the second-highest paid offensive player on the 49ers behind wide receiver Deebo Samuel. Williams, 36, is the third-highest paid left tackle in the game with an average of...