A song lyric asks, "What's love got to do with it?"
The football version could be, "What's the 40-yard dash time got to do with anything?"
Manti Te'o might be able to play in the NFL. Or not. He might be able to play for a year or for five years or 15 years. Or not at all. He might be an all-pro middle linebacker, merely serviceable or special-teams fodder. Or none of the above.
The pressing question Tuesday was how much of Te'o's future depends on the 40, which might be the silliest measurement in all of sports outside of hat size.
Te'o ran a 4.82 at the NFL Scouting Combine in February and a tenth of a second faster Tuesday during workouts at Notre Dame's pro day.
ESPN draft guesser Mel Kiper pontificated that the ND product is a certain first-round draft choice based on the improvement.
A poor performance in the BCS title game against Alabama and a make-believe girlfriend on social media clouded Te'o's future. On the other hand there were his award-winning production during four seasons at Notre Dame and his leadership qualities.
The 40-yard dash in South Bend must have been a tiebreaker of sorts for Kiper.
Look, you can guess along with scouts about Te'o's NFL prospects and you can add in as much significance as you want to that dang 40-yard dash time.
I'm the last guy to trust with evaluating any football prospect. Heck, I don't even know how to operate a stopwatch.
What I do know is that when experts talk about Te'o it sounds a lot like the doubts when the Bears drafted Mike Singletary in 1981's second round. He was too short at 6-feet, too light at 230 pounds, and not the fastest guy either.
"About a 4.6," Singletary was quoted as saying a couple of years ago when asked what his time in the 40 was.
Singletary also was asked whether 40 times are overrated.
"Absolutely," he reportedly said. "The No. 1 thing, when you look at film: the football player. The teams that win year in and year out are the teams that have football players."
Is Te'o a football player? It sure looked like it during his Notre Dame days, at least until that January night against Alabama.
If Te'o isn't a football player, especially an NFL football player, it'll be because of more than his time in the 40. So many fast guys play slow in the NFL and so many slow guys play fast.
When scouting is referred to as an inexact science, that's what they mean.
A lot of Te'o's chances in the NFL will depend on whether he gets lucky like Singletary did and joins a team with defensive tackles like Dan Hampton and Steve McMichael to shield him from blockers. Do the Bears have anyone like that now?
Speaking of middle linebackers, consider the word on Dick Butkus, the greatest ever to play the position.
Former Bears teammate Ed O'Bradovich told espnchicago.com in 2011 that Butkus took "three days to run a 100-yard dash" but for 20 yards in any direction "nobody was quicker."
While wondering whether anyone timed Te'o in the 20 going north, south, east and west, consider what Doug Buffone told espnchicago about playing next to Butkus:
"There's the 40 speed and there's the speed when you get on the field, recognition of what's going on and getting there before the other guy, and that's what Dick had."
Does that describe Te'o, too, or doesn't it?
What's intriguing is that NFL scouts don't seem to know.
All those stopwatches Tuesday at Notre Dame's pro day probably didn't help decide because, you know, what's a player's time in the 40 got to do with it anyway?