49ers general manager John Lynch expresses optimism about the team being able to reach a deal with Trent Williams. (1:05) SANTA CLARA, Calif. -- With the start of the early free agent negotiating window 13 days away, the San Francisco 49ers have a big piece of business they're hoping to get done soon: figuring out the contract situation for left tackle Trent Williams. As it stands, Williams is entering the final year of his deal and carries a salary cap number of $38.84 million, which includes a base salary of $22.21 million and has a $10 million option bonus due in the coming weeks. That option bonus has increased the urgency to strike a deal that works for both sides. Sources told ESPN's Adam Schefter on Tuesday that Williams and the Niners are "struggling to find a contractual solution." Soon after, Niners general manager John Lynch spoke to reporters at the NFL combine in Indianapolis and offered a more optimistic perspective.…