Derek Jeter's injury took center stage on Opening Day, overshadowing RHP Bret Prinz's likely season-ending groin tear. Prinz collapsed while pitching in relief of LHP Randy Johnson in the eighth inning of Arizona's home opener against the Dodgers. An MRI later revealed that the injury was probably every bit as painful as it looked on the field, as Prinz's right groin muscle was torn away from the bone.

While a strained groin likely would have sidelined the right-handed reliever for six to eight weeks, Prinz now seems unlikely to return before the end of the season. I certainly don't expect him back before the All-Star break.

Rather than immediately call up a pitcher to replace Prinz, Arizona decided to go with only 10 pitchers for the rest of the series with LA. The Diamondbacks promoted C-R Rob Hammock from AAA to fill Prinz's roster spot. Four days later, they demoted Hammock in order to call up a pitcher, as traveling to Colorado with only 10 pitchers would have been ill-advised. We expected Hammock to remain in the minors for the majority of the season, but C-R Rod Barajas injured his left hamstring in Sunday's game, so Arizona recalled Hammock yesterday.

Arizona drafted Hammock out of the University of Georgia with their 23rd round pick of the 1998 draft. He spent the remainder of that season in the Rookie-level Pioneer league and then advanced to A+ High Desert in the California League for the 1999 season. Hammock split 2000 between High Desert and AA El Paso in the Texas League. In 2001, he bounced between AA El Paso, A South Bend in the Midwest League, and A+ Lancaster in the CAL before settling at El Paso last year. The 25-year-old has demonstrated solid plate discipline and power skills through AA and will likely warrant a steady major league job after a season of AAA. His ability to play the infield and outfield corners should help him hold a roster spot. I don't expect him to excel offensively without time in AAA, but at this stage of his development, he should be able to produce sufficiently to serve as Barajas' replacement.

Barajas' hamstring strain is not severe, so he may be able to return in as little as three weeks. As Hammock should serve in a back-up role, Barajas' injury will give C-R Chad Moeller a chance to lay claim to a larger percentage of the playing time behind the plate. Hopefully, Moeller will be able to showcase his offensive skills, which are superior to those of Barajas.

RHP Scott Service was the pitcher Arizona promoted prior to their series in Colorado. MLB.com writer Steve Gilbert points out in an article on the Diamondbacks' site that Arizona "planned to call up pitcher Brandon Webb. . . but rules do not allow the recall of a player from the minor leagues 10 days after he's been sent there, although Webb was sent out in mid-March. The transaction date is the beginning of the season, except in the case of injury."

I found this interesting as I was aware of the 10-day period but had not previously known of the transaction dating. While Arizona should be chastised for allowing ignorance of the rules to interfere with their preferred course of action, I believe the snafu actually worked in their favor. The Diamondbacks drafted RHP Brandon Webb out of the University of Kentucky with their 8th round pick of the 2000 draft. He made one start with their Rookie-level Arizona League team and then finished that season as a reliever at A South Bend. Webb spent all of 2001 at A+ Lancaster and the majority of 2002 at AA El Paso with only one start at AAA Tucson.

While at El Paso, he compiled a 122:59 K:BB with 141 H and 4 HR allowed in 152 IP for a 3.14 ERA over 26 appearances including 25 starts. His walk rate is a tad high, but his strikeouts and HR/9 look promising. I believe the 23-year-old is better served by remaining in AAA for now, but he looks like a solid prospect. Considering RHP John Patterson appears to have fallen out of favor with the Diamondbacks, Webb could contribute as soon as the second half of the season, if he transitions smoothly from AA to AAA and the Diamondbacks run into injury problems in their rotation.

RHP Oscar Villarreal, who stole the rotation spot expected to go to Patterson, made his major league debut in relief when Prinz came out of the Diamondbacks' March 31st home opener due to his injury. The 22-year-old wasn't on the mound long, as he needed only one pitch to strikeout RHP Hideo Nomo, who Prinz had left in mid-count. That out ended the inning and Arizona did not bring him back out to pitch the ninth. Villarreal was available in relief for the first week of the season and made four appearances out of the pen, because Arizona did not need a fifth starter immediately. He will make his first major league start today.

The severity of Prinz's injury made it simple for them to open up a 40-man roster spot by moving him from the 15-day to the 60-day disabled list. When the Diamondbacks signed Scott Service to a minor league contract this off-season, I mentioned him as a pitcher who could provide solid relief work if called up during the season. Prinz's upside is greater than that of Service, but the 36-year-old should be a capable replacement.