Some guys fly under the radar. Here are five weapons to watch on potential playoff teams:

1. Brandon Crawford's defense. I know, I get it. Maybe you live on the East Coast. You don't watch much baseball from the left side of the country. So maybe you were surprised watching the Giants in the postseason and seeing Crawford's D, especially his cannon of an arm. Crawford ranked third among NL shortstops in Defensive Runs Saved at plus-12 and it's going to be fun watching him and Atlanta's Andrelton Simmons compete for Gold Gloves in upcoming years.

2. Oakland's outfield defense. The Braves may have had one of the best outfield defenses in decades last year with Michael Bourn, Jason Heyward and Martin Prado, but with Bourn a free agent my pick for best outfield in 2013 goes to the A's. In Josh Reddick and Yoenis Cespedes, the A's have two of the best arms in the business. Cespedes was inconsistent in center but will move full time to left field, clearing the way for Chris Young to take over in center. He was an elite defender with the Diamondbacks (fourth among outfielders in Defensive Runs Saved over the past three seasons) and should be an improvement over Coco Crisp, who will presumably shift to a backup role, but he can fill in at all three spots and provide average defense. There's a reason Oakland's young pitching staff was good last year and a reason it should be good once again.

3. David Hernandez's slider. I mentioned Hernandez on my Team USA roster piece Monday and how he quietly developed into one of the game's premier relief pitchers in 2012. Hernandez sets up his slider with a mid-90s fastball and if he gets ahead in the count, the slider is deadly. In 112 plate appearances ending with a slider in 2012, batters hit just .088 ... with 71 punchouts. J.J. Putz is back as closer but Hernandez is the big weapon in Arizona's bullpen.

4. Steve Delabar's splitter. The Blue Jays picked up Delabar in midseason last year from the Mariners for backup outfielder Eric Thames. Delabar -- you may know him as the former school teacher with a steel plate and screws in his arm -- held opponents to a .193 average and fanned 92 in 66 innings. Like Hernandez, a mid-90s fastball sets up his off-speed pitch and batters hit just .148 off his split. Delabar's fastball is pretty straight and he needs to curb his home runs -- he allowed 12, although just three after joining the Jays -- to become an elite reliever in Hernandez's class, but if he does that the Toronto bullpen will be much improved.

5. Ross Detwiler's fastball. The Nationals are the best team in baseball entering the season in large part because of the depth of their rotation. Detwiler would be a No. 2 on many teams, but in Washington he's the No. 4 or 5 guy. He went 10-8 with a 3.40 ERA in his first full season in the rotation. He throws his fastball more than any starter in baseball, about 80 percent of the time. It's really a hard sinker, so while Detwiler may not generate the big strikeout totals he does induce groundballs -- just over 50 percent last year. Detwiler crushed lefties -- .170/.255/.259 -- so if he can improve his curveball and changeup against right-handers, he can take his game to the next level. And make the Nats that much tougher.