"We have been told he has been recovering tremendously," Mandel, 64, said of Cowell. "I would not count him out before the end of this season."
"You're right," Klum, 47, agreed.
"He's had a six-hour operation and he is already on his feet, which is above and beyond expectation, so I am thrilled," Mandel added. "I love the guy, I miss the guy, and my hearts and minds are with him and each and every moment."
While his fellow AGT judges were sad to see Cowell sit out this week's episodes, they were thrilled to temporarily welcome Kelly Clarkson in his place.
"Obviously we miss the boss. There is no one who could actually take his place, even though Kelly did absolutely amazing today," Klum said. "[She did] an amazing job and she had so much fun, but no one is like Simon. That is just the way it is."
"I think that Simon is irreplaceable and Kelly was brilliant," Mandel agreed. "She's done it. She's a pro. She brings something to the table."
If Cowell's injury continues to keep him from his AGT duties, Mandel has one thought about who could step in to guest judge.
"I would love to see Judge Judy. I love her judging," he said. "She's honest, she says it like it is, and I would love to have her at the desk."
When it comes to Vergara, though, she just wants things to go back to normal.
"I want Simon back. This is my first time. I want things to be normal," the 48-year-old actress said. "I want the coronavirus to go away now."
In addition to having to cope with a personnel change-up, the judges have also been tasked with putting on an epic show with coronavirus-related precautions and adjustments in place, including social distancing measures, frequent testing, and an on-set nurse.
"We are super thankful that America gets to see this talent and they get to vote on all these amazing people... I am super thankful that this could go on. It was a lot of fun too," Klum said, before praising the production for making the judges feel like they weren't alone without a live audience.
"We came in the room and it was like all these people from America were behind us [on] all these little screens... I mean it was amazing," she said. "It felt like we were not alone. I mean, we know people are watching at home, but it actually felt like there's a lot of people there in that room with us. It was really cool."
Vergara agreed with Klum, calling the experience "better than good."
"It felt big, but it felt perfect. I didn't know what I was walking into because it's my first time in the finals, so... I didn't even know what to expect. And then I was worried because we don't have the audience, that we sometimes feed from their energy, but it was spectacular," she said. "I would forget that I was there working and just get fascinated by what the people are doing. I had the best time."
Though Mandel has had a decadelong AGT tenure, he, like first-time host Vergara, simply "didn't know what to expect" from the episode.
"Walking into that room was such a surprise, it was bigger and more spectacular production than we've ever had," he said. "This is something I needed personally, to watch these people with hopes and dreams come true, and to be in this room and with this production company. This has been my panacea for this pandemic."
America's Got Talent airs Tuesdays and Wednesdays at 8 p.m. ET/PT on NBC.