After getting eviscerated in Oakland, Juan Cruz now finds himself back in the NL. He’s the long-man in the Diamondbacks’ bullpen; but with a rotation featuring Orlando Hernandez, Claudio Vargas, and Russ Ortiz, it probably won’t be long until Cruz is getting his shot to start.

I banished Cruz from all my cheat-sheets last year, after watching his velocity drop and his control disappear in the AL. But there’s always been something about this guy that suggested a $20 pitcher: a high-90s sinking fastball with Pedro Martinez-movement.

This spring, Juan’s 0.00 ERA/.109 OBA/13 IP/16:4 K:BB. Although he’s kicked around the league for a while, he’s just 26 years old. That’s prime breakout age for a guy who was supposed to be the next great Cubs starter.

He went down to AAA last year and threw 2.40 ERA/1.05 WHIP/75 IP/51 Hits/90:28 K:BB. His minor league K rate is 9.46/9 IP. But his career BB rate is 4.56/9 IP in the majors, and 3.54 in the minors. That’s why he’s been such a bust: he has no command.

It seems like there have been a lot of big-time K pitchers who came up, struggled with command for a few years, and then suddenly broke out. After walking 3.67/9 IP in the minors, John Patterson finally put his game together and became one of the NL’s Top 5 starters in ‘05. This is the same guy who had a 5.03 ERA in ‘04, and walked 46 in 98 IP. Last year he walked 68 in 185 IP.

Before breaking out at 29 years old, Jason Schmidt was an average-below average pitcher. Then, in ‘02, something clicked, and his hit rate dropped from 9.27/9 IP, to 7.19/9 IP. His Ks climbed from 6.26/9 IP, to 9.52.

Chris Carpenter needed 6 MLB seasons and 1 shoulder surgery before he figured it out.

Another thing these guys have in common: they all pitch in the NL. And they all throw excellent sinkers.

Cruz seems likely to figure it out at some point. Maybe a new pitching coach can do it for him. But as he continues to rack up experience, the possibility for a breakout season seems right there on the horizon. Like a lot of players, Cruz is not the kind of guy who’s not going to gradually shave points off his ERA and WHIP on the road to becoming a 175 K pitcher. He’ll be bad until he’s good, and then you’ll be rushing to pick him up.

Update (May 16): Cruz is back in the rotation, but his fastball is down to 90-91. Forget him; he’s probably never going to be an effective MLB starter.