I'm not convinced he's the closer of the future in Oakland. While it's likely Dotel moves on, remember the name Jairo Garcia. While Street has gotten most of the pub, Garcia lit up 3 levels - A, AA, and AAA - on his way to a brief cup of coffee in September. Although he didn't fare well in his brief stint with the A's, his minor league numbers from this year are staggering:
Total over all three levels:
36 H allowed
1 HR allowed
Reports say he's a Dotel clone with a lightening fastball and a dirty slider. I tend to think Garcia will actually be the eventual closer as Street doesn't have the velocity. Regardless though, he and Street will be a very good 1-2 punch at the end of games in Oakland's near future.