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8/31/2014 7:19 P.M. ET

Pedroia out until concussion protocol cleared

ST. PETERSBURG -- Red Sox second baseman Dustin Pedroia will have to pass Major League Baseball's concussion protocol before getting back on the field, manager John Farrell said Sunday morning.

Pedroia sat out Sunday's game against the Rays, and after Boston's 3-0 win, Farrell said he did not expect Pedroia to be able to play in Monday's series finale.

Pedroia experienced symptoms consistent with a concussion after taking a blow to the head in Saturday's loss to the Rays at Tropicana Field. Logan Forsythe unintentionally struck Pedroia in the face while tagging to second base as he tried to swim-move around Pedroia's tag.

"[He's] improved this morning," Farrell said before Sunday's game, for which Pedroia was out of the lineup as expected. "We're holding him out for obvious reasons. We hope this is a short-term thing, but we'll have to go through the normal protocol, and that is continued exams by doctors and making sure that there are no symptoms -- no fatigue, no dizziness, the things that are consistent with a concussion."

After the game, he said Pedroia was about the same as before.

Brock Holt started at second base Sunday.

Pedroia was in the Boston clubhouse before the game. Because rosters expand on Monday, the Red Sox will not need to place him on the seven-day concussion disabled list. But Pedroia will have to pass the same tests in order to play.

"We have to follow the same protocol just to get him back on the field, yes," Farrell said. "Once you submit paperwork that there's been an impact to the head, then there's the follow-up protocol that's got to be followed."

The paperwork the Red Sox filed is required after incidents where an impact to the head is involved, Farrell said.

Farrell did not want to definitively categorize Pedroia's injury as a concussion, although Pedroia was examined by a Rays team doctor Saturday night.

As of now, Pedroia will not need to take additional measures -- such as seeing University of Pittsburgh concussion specialist Dr. Michael Collins, as several Red Sox have done in recent seasons after sustaining concussions.

"I don't know that we're at that point," Farrell said. "When symptoms don't clear up after a prolonged period of time, then you're going to those next steps. There's a lot of gray area in this type of thing when you're dealing with fatigue, you're dealing with equilibrium issues, but those weren't present last night. It was a little bit of dizziness when he first was impacted, but that cleared up as the night went along."

Worth noting

• Jemile Weeks, whom the Red Sox acquired from the Orioles for Kelly Johnson after Saturday night's loss to the Rays, was active for Sunday's 1:40 p.m. ET game between the clubs at The Trop.

Weeks arrived around the third inning, Farrell said after the game, and did not play.

• When rosters expand Monday before Boston's series finale against the Rays, the Red Sox will likely only add one pitcher for bullpen depth, Farrell said Sunday.

Farrell said the team will add a few more players after it arrives in New York on Tuesday for a series against the Yankees, but because of Monday's day game and a quick turnaround to New York, a single arm will be the only immediate addition.

• The Red Sox will limit the usage of relief tandem Junichi Tazawa and Koji Uehara in September, Farrell said.

"We've met. They're understanding of the usage and how frequent it might be," the Boston skipper said. "The game is going to dictate when their usage is. And yet, we also want to be careful and make sure there's appropriate rest."

Farrell said that in save situations on days when closer Uehara might be unavailable, Edward Mujica would likely close games.

• Recent acquisition Rusney Castillo made his Minor League debut in Fort Myers, Fla., on Sunday in the Gulf Coast League finals. The 27-year-old Cuban outfielder, who started at designated hitter and batted leadoff, singled through the left side in his first at-bat and finished 1-for-2.

Castillo will play five innings in center field on Monday, Farrell said.

David Adler is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.