A curveball in the outfield

MINNEAPOLIS -- The team with two center fielders is now down to none.

Mike Cameron did not return to Boston with the Red Sox after their 8-0 loss to the Minnesota Twins, as he sought to learn the origins of lower abdominal pain that caused him to be scratched from the lineup Thursday. Cameron's agent said Friday morning that the initial diagnosos was a possible kidney stone and that Cameron would be examined by team doctors in Boston on Friday.

"I'm just pretty sore,'' Cameron said Thursday. "It's unusual. I've never experienced anything like it.

"I was able to come here and stretch, try to get loose, went outside and ran, but could hardly even walk after that. If there was a dog after me, I had no chance today.''

Jacoby Ellsbury, meanwhile, does not look like he'll be returning to the lineup in time for the start of this weekend's series against the Tampa Bay Rays. Ellsbury, who did not play while the Twins took two out of three from the Red Sox in their spectacular new outdoor playground, Target Field, is still recovering from Sunday's collision with third baseman Adrian Beltre in Kansas City.

"I still can't really take a deep breath without getting a sharp pain,'' Ellsbury said. "I guess it's better safe than sorry, to see exactly what it is. I'm sure there's swelling, but I don't want to make any predictions or whatever on what's going on."

Ellsbury is due to see a doctor in Boston on Friday to be re-evaluated, he said.

There's a possibility that both Cameron and Ellsbury could be headed to the disabled list -- Ellsbury retroactive to last Sunday -- which would necessitate a call for reinforcements.

"We haven't ruled anything out,'' manager Terry Francona said. "That's why we're having both of 'em looked at, to see where we're situated.''

If both Cameron and Ellsbury need to be sidelined for any length of time, the logical call-ups from Pawtucket are Darnell McDonald, the 31-year-old journeyman who was the Orioles' No. 1 pick in 1997, and/or Josh Reddick, who was one of the team's top hitters in spring training.

McDonald has started five big-league games in center field over the course of his career, and started seven games in center for Triple-A Louisville last season.

Reddick has been playing center field for the PawSox but is batting just .138 (4 for 29). He did not play Thursday in Pawtucket's game in Buffalo, manager Torey Lovullo saying he wanted to give him a "mental break," but he may also have been held out as a contingency because of the situation involving Cameron and Ellsbury.

"[Reddick] has been grinding away at things pretty good," PawSox manager Torey Lovullo told ESPNBoston. "I thought about [giving him a day off] a couple of days ago, but he responded with a couple of hits. The best thing about Red is that you wouldn't know by looking at his pace of play that he's not hitting the way he wants to. He's as good as anybody we have getting down the line. He's laying out for balls in the outfield. He's just doing a great job all the way around outside of getting his base hits. It's going to come and I just wanted to give him a mental break and let him catch his breath."

Bill Hall, originally scheduled to start in left Thursday, instead played center, where he had not made a start since 2007, when he was with Milwaukee. Hall caught three fly balls hit his way, but also mishandled a ground-ball single by J.J. Hardy, allowing runners to advance an extra base.

It was one of three errors by the Sox, who had come into the game having committed just two errors in the season's first eight games. Adrian Beltre's throw pulled Kevin Youkilis well off the bag after the Sox third baseman had made a nice stop on Hardy's sixth-inning smash. Instead of two outs and nobody on, the Twins had a man on with one out, and went on to score twice off starter Tim Wakefield, expanding their lead to 6-0.

The other error was made by catcher Victor Martinez, who continues to throw high to second base, this time overshooting his mark while Michael Cuddyer was advancing to second on a wild pitch by Wakefield in the fourth. Cuddyer took third on the play, but did not score.

"It was a very ugly game today, and it began with me on the mound,'' said Wakefield, who gave up 10 hits and a walk in 5 1/3 innings against a Twins team that batted .312 (34 for 109) in the series.

Meanwhile, Francisco Liriano, showing the kind of slider reminiscent of the wicked pitch he threw before undergoing reconstructive elbow surgery in 2006, shut out the Sox on four hits through seven innings.

All three of Boston's starting outfielders -- Ellsbury, Cameron and J.D. Drew -- have had physical issues already this season. Drew, who said he'd been experiencing neck stiffness for much of the previous week, had sat out Sunday's game until Ellsbury's collision with Beltre.

Drew played the entire Minnesota series, but since his single Saturday is hitless in his last 11 at-bats, and has struck out in 8 of them, including three times Thursday, which suggests he may not be feeling right. Drew's average is down to .143, and he now has 13 strikeouts, as many as David Ortiz.

Cameron, meanwhile, was also off to a slow start offensively, batting .217. He has more strikeouts (7) than hits (5).

The three outfield starters have combined to drive in a total of three runs so far this season. The most productive outfielder so far has been Jeremy Hermida, who originally wasn't scheduled to face Liriano Thursday and went hitless in three trips. Hermida has three doubles and a home run and has knocked in six runs while batting .294.

"A couple of guys are going to start hot, a couple of guys are going to start cold,'' Francona said. "And a few guys are going to be in between.''

Gordon Edes is ESPNBoston.com's Red Sox reporter. He covered the Red Sox for 12 years and has reported on baseball for 25 years. Ask a question for his next mailbag here.