Spieth said he would put James in the same category as Johnson. The wide receiver apparently saw this, because the Lions' website said Johnson sent Spieth a signed football and jersey to his office in Dallas while the U.S. Open was going on this weekend.
Spieth's agent, Jay Danzi, confirmed to ESPN.com that his client received the "kind gift."
"I would say yes," Spieth told ESPN when asked the James question. "But I'd put into that same equation Calvin Johnson and Cam Newton. As an athlete, I feel like Calvin Johnson can do anything. Cam Newton's hands are twice the size of mine; he's a freak athlete.
"Or Bo Jackson still might be the best."
On the autographed football, Johnson wrote, "To Jordan Best of luck on tour," then signed his name.
Spieth won the U.S. Open by 1 stroke over Dustin Johnson after Johnson three-putted on the 18th green. It was the second straight major win for Spieth, who go for the third leg of the grand slam in the Open Championship at St. Andrews next month.
Calvin Johnson retweeted the initial Lions story Monday. On Sunday, Johnson was clearly watching the U.S. Open as he congratulated Spieth on Twitter soon after the 21-year-old's win at Chambers Bay.
Johnson rejoined Twitter on Friday to speak out about the shootings in Charleston, South Carolina. Since then, Johnson has tweeted about his foundation, Spieth and the Shawn Porter-Adrien Broner boxing match, and to Tigers pitcher David Price about cleats.
Jordan Spieth: SportsCenter Conversation
Analyst Tom Rinaldi talks with Jordan Spieth about his U.S. Open win and who he thinks is the best golfer in the world.