Yankees- Robinson Cano- Cano came up in 2005 to replace the pathetic Tony Womack and his success was key to convincing the Yankees to rebuild the farm system. Since coming up he has become one of the best second baseman in the game. He got a 4 year extension this year, an extremely rare move for the Yankees to make with a young player with a few more years of arbitration left. Cano's biggest problem is his plate discipline. He`s constantly swinging at balls out of the strike-zone. If he can solve this problem then theirs no limit to what he can be. His defense also made leaps and bounds last year. Baseball Prospectus has him saving 26 runs more than the average 2nd baseman (This would translate to about 3 wins) but anyone who watched the games last year could have seen that. Although at times he seemed to lose focus and make stupid mistake as has happened in the past he displayed great range all year. All in all he`s a great young player and the Yankees were smart to lock him up.
Red Sox- Dustin Pedroia- Pedroia got his first chance in the ML's in 2006 and bombed in the 20 or so games he played. Last year, he came up early in the season to play second. Although he intially did not do well and earned a lot of bad puns about him being worse than Cano from Yankees fans. He turned his season around though and posted a BA/OBP/SLG% of .317/.380/.442. He`s a year younger than Cano as well. Pedroia is going to be a great player and the Red Sox won't be having any problems at second base for a while. His defense is also solid and above average.
Conclusion- Yankees- This is the closest one yet and its a very tough call. Pedroia had the better offensive numbers last year but Cano has the better defense and is a little more proven. In the end I just decided that Cano is likely to improve while Pedroia might fall off a little. Maybe its just my bias but I`m leaning towards Cano.