SANTA CLARA >> Brandon Aiyuk’s comeback from last season’s knee injury is going so well, “it’s kind of incredible how well he’s healing,” 49ers general manager John Lynch said Thursday on The Pat McAfee Show.

Aiyuk appeared in good spirits and impressively agile while watching the 49ers’ minicamp practices on Wednesday and Thursday. Whether or not he will be cleared in time for the Sept. 7 season opener at Seattle, Aiyuk’s work habits are impressing the 49ers.

Aiyuk tore the anterior cruciate and medial collateral ligaments in his right knee in an Oct. 20 loss to the Kansas City Chiefs, then underwent knee reconstruction the following month by Los Angeles-based surgeon Dr. Neal ElAttrache.

“Brandon is doing a tremendous job coming back,” Lynch said. “These guys that are incredibly skilled athletes, they tend to heal a lot faster. It’s kind of incredible how well he’s healing. He’s putting in the work. We’re proud of Brandon. We’re looking forward to him being part of this team moving forward.”Aiyuk, a 2020 first-round draft pick, seemed willing to leave the 49ers a year ago before contentious contract negotiations led to a late-August deal (five years, $120 million). An April 1 roster bonus of $22.9 million affirmed the 49ers’ commitment to him this season.

“We made a big investment in him. We’re proud to have him part of our franchise, and we’re looking for big things from him,” Lynch added. “We’re going to let him get right before we get him back on that field. But he’s an important part of this team.”

Aiyuk figures to open training camp on the Physically Unable To Perform list, and he’ll miss at least the first four games if he starts the season on that list.

Aiyuk did not speak to reporters during the 49ers’ offseason program, which officially concluded on Thursday with a private, family-oriented picnic.

“He is making his way back,” coach Kyle Shanahan said Tuesday.