Axios

Thanks to an exploding NBA salary cap and a wild NHL postseason that saw many of the league's highest-paid players sent home early, the salary disparity between the two leagues has never been more glaring.

Like most professional sports leagues, the NFL focuses a ton of effort on finding and developing new revenue streams. But there's one resource that the league has yet to tap: jersey advertisements.

Why it matters: If every NFL team had a sponsorship patch like the ones you see in the NBA, it could net the league at least $220 million annually in added revenue — and that's an extremely conservative estimate.

Baseball's attendance is off to another slow start, and while those numbers will creep up during the summer months, the early drop is still indicative of a continuing and startling trend.

By the numbers: Between 2008 and 2018, the league's average attendance decreased by 14%. This season, March–April attendance was roughly the same as last year, but seven teams saw double-digit dips, led by the Blue Jays (25% drop-off), Twins (18%) and Giants (17%).