In an instant, the former Alabama star went from believing he was about to become a member of the Saints via the 32nd pick in the first round to becoming a Niner with the 31st selection.
To put it mildly, Foster found himself in an awkward spot.
"That's a funny story," Foster said at his introductory news conference Friday.
According to Foster, his girlfriend, who is from Baton Rouge, Louisiana, was speaking to the Saints just before they were about to use the 32nd pick on Foster when she looked down and saw a San Jose, California, area code. She handed the phone to Foster, who was unsure what to do.
In the run-up to the draft, Foster had spent a lot of time with Niners general manager John Lynch and coach Kyle Shanahan. Lynch said Thursday night that the 49ers had met with Foster at the NFL scouting combine and hosted him on a pre-draft visit. Lynch and Shanahan had also spoken with Foster via FaceTime, and the Niners sent a contingent to Tuscaloosa to spend time with Foster before the draft.
Because of all that, and Foster's affinity for former San Francisco linebacker Patrick Willis, Foster said he wanted to be a Niner.
"So I clicked over to the San Francisco 49ers and I said hello, with the New Orleans Saints still on the line," Foster said. "I wanted to be a 49er so bad."
Unaware that the 49ers had just traded with the Seattle Seahawks to move from No. 34 to No. 31, Foster informed Lynch that he was going to the Saints at No. 32.
"The (Saints) wanted to pick me, but (the Niners) had the 31st pick so they couldn't," Foster said. "I told ... John Lynch it was too late. He had the 34th pick; it was too late and the Saints are about to get me."
But Lynch informed Foster of the trade and said he was about become a 49er. The Saints, meanwhile, waited on the other line but never heard from Foster again.
"I hung up," Foster said, sheepishly.
After his news conference, Foster clarified to ESPN that he didn't mean to hang up on the Saints, but he had to continue his conversation with Lynch.
"It was no disrespect to the Saints or none of them, it was just at that moment, he told me he was trading out from the 34th to the 31st," Foster said. "It was a crazy story."
When Foster wasn't relaying the story of his wild draft night, he was answering questions about his injured right shoulder. Foster said Thursday night that his shoulder is at about 90 percent and he will be ready for training camp.
Reports surfaced Friday morning that Foster would need a second surgery on the shoulder, which was a primary reason Foster fell to No. 31. On Friday, Foster said he would not need another surgery.
"I've made progress," Foster said. "I'll be limited at OTAs. Training camp, I will be full go, but if it was my decision I would be ready right now.
"I'm fine. I'm on schedule."