Ryan Phillippe flashes his toned abs while watching he & Reese Witherspoon's son Deacon play flag football

 Ryan Gosling's got some competition!

Another sexy Ryan -- Ryan Phillippe -- showed some skin at son Deacon's football game Saturday.

The cute dad heated things up on an already scorching LA afternoon, as he wiped the sweat from his face with his t-shirt, exposing his toned tummy.

Meanwhile, Ryan's ex, Reese Witherspoon, isn't looking so hot these days after her arrest in Atlanta with hubby Jim Toth. Who would've thought that America's Sweetheart would be the one thrown in the slammer, while her ex is the doting, responsible dad?!