SS - Alex Rodriguez - (1/26/2001) Signed as a Free Agent with the Texas Rangers.
After posting an absurd batting line in 2000 with the M's and finishing 3rd in MVP voting, A-Rod left the Pacific Northwest on a mission to find the owner who would open his wallet up the farthest. Which, props to Alex, he was able to do just that. At the time, this deal (10 Years/$252 Million) was the largest deal, not only in the MLB but in all of sports.
Safe to say the Mariners were not able to fork up that amount of money. But what if they were? Although A-Rod produced well in his 7 years in Seattle, imagine if we were able to keep him in 2001 on the winningest team in MLB history. Yes, we likely wouldn't have also signed Ichiro at the time, but who knows? Would his offensive production have been the catalyst to help the Mariners at least reach the World Series for the first time?
After leaving Seattle, Alex rattled off a string of 8 straight All-Star appearances and won the AL MVP 3 times (2003, 2005, 2007). He is a sure-fire hall of famer if not for his off-the-field decisions, and although many people are not very fond of him for this, no one can argue that he wouldn't have helped the Mariners make more playoff pushes. With that, A-Rod gets the nod at Shortstop.