Which Mets first baseman, now a broadcaster, was featured in a famous 'Seinfeld' episode?

Which Yankees player was nicknamed "Donnie Baseball"? Which Mets pitcher was nicknamed "Doc" and won the 1985 Cy Young at age 20? Which Mets outfielder was nicknamed "Straw"? Which Mets batter's ground ball went through Bill Buckner's legs in the 1986 World Series? Which Cubs broadcaster and former third baseman had his No. 10 retired by the team? Which Cubs second baseman, nicknamed "Ryno," won the 1984 NL MVP? Which Expos and Cubs outfielder, nicknamed "The Hawk," won the 1987 NL MVP? Which Mariners outfielder won both AL MVP and Rookie of the Year in 2001?