Today in sports: father of the "Greatest Show on Turf" offense says he's done coaching football, the University of Miami will no longer let donors buy players "occasional meals," and Tim Tebow will not be a guest analyst for CBS this weekend.

Mike Martz, engineer of the pass-happy offensive gameplans that helped the turn-of-the-millennium St. Louis Rams reach two Super Bowls in three years, says he's done with coaching at the age of 60. Martz was offensive coordinator of the 1999 Rams team that defeated the Tennessee Titans in Super Bowl XXXIV and scored 526 points during the regular season, which at the time was second most in NFL history. Two years later, he was the head coach of the Rams squad that lost to the 14-point underdog New England Patriots in the biggest upset Super Bowl history. Martz was bizarrely fired by the Rams in 2005 after taking a medical leave of absence, but resurfaced as offensive coordinator of the San Francisco 49ers, Detroit Lions, and Chicago Bears, improving each team's offense before departing on less-than-ideal terms. This was particularly true of his time in Chicago, which ended earlier in the month when head coach Lovie Smith -- his defensive coordinator during the Rams glory years -- helped to push Martz out the door after two seasons.  [Chicago Sun-Times]

Five months after jailed University of Miami booster Nevin Shapiro told Yahoo that he handed out "thousands" of impermissible benefits -- including cash and sessions with prostitutes -- to Miami athletes over an eight-year period, the school has alerted backers that they are  "no longer permitted to entertain student-athletes with an occasional meal." An "occasional meal" wasn't what got Shapiro in trouble and is permitted by the NCAA, but apparently the school doesn't investigators to think that those occasional meals are coming with a side dish of cold, hard cash. (Anymore.) [Miami Herald]

CBS apparently offered Tim Tebow a spot as a guest studio analyst during Sunday's AFC championship game, only to have the Denver Broncos quarterback turn them down. Meanwhile, CBS Sports' vice president of production Harold Bryant was forced to deny that the invitation was extended because Tebow endorses Subway, which also happens to be the sponsor of the network's pregame show. [USA Today]

Also on the Tebow front: Broncos president John Elway said at a press conference yesterday that he "think[s] Tim's earned the right to be the starting quarterback going into training camp next year." That didn't strike anyone as a ringing endorsement, least of all former Baltimore Ravens coach Brian Billick, who went on NFL Network last night and said that Tebow needs to lose weight and work with a "quarterback whisperer" (like Brian Billick!) if he wants to be a functional starter next year. [AP]

There were just 20 players born in Puerto Rico on the opening day rosters of Major League Baseball clubs in 2010, down from 45 in 1999. The decline is being blamed on an MLB rule change in 1990 that made the country's amateur players eligible for the first-year player draft, which means they have to finish high school before signing a big league contract. Amateurs from Venezuela and the Dominican Republic, who are not included in the draft process, can sign with team as free agents as soon as they turn 16. This has limited the exposure for players who aren't playing in one of Puerto Rico's big cities, and also encouraged teams to shift their scouting hubs elsewhere, where they can cultivate younger talent with fewer restrictions  [The New York Times]

We're not sure why the Kansas City Star decided to run reporter Kent Babb's investigation into the weird and secretive corporate culture the Kansas City Chiefs have installed since hiring Scott Pioli as general manager three years ago, because it's an odd, fascinating piece. What's the juiciest detail? Probably that former head coach Todd Haley "repeatedly checked his office for listening devices" and stopped talking to people on the phone because he feared management was listening in. (The team denied that charge, while Haley didn't respond to Babb's requests for an interview.) Former Chiefs employees interviewed in the article also allege that Pioli, who joined the Chiefs after nine years working in the famously exacting and secretive front office of the New England Patriots, would throw tantrums over silly, seemingly pointless things, like "the temperature in his office, the radio signal in the weight room, and how much the organization spent annually on coffee," and that he once held a front office meeting after he found a discarded candy wrapper in a hallway at the team's headquarters. [Kansas City Star]