NEW YORK -- New York Mets left fielder Jason Bay was placed on the seven-day concussion disabled list Saturday after leaving Friday night's game against the Cincinnati Reds following his crash into the left-field wall.
Infielder Justin Turner was activated.
Bay fell awkwardly as he skidded into the corner and appeared to hit his head as he tried to field Jay Bruce's second-inning hit that resulted in an inside-the-park home run.
He struggled to his feet before finally throwing in the ball.
As Bay was escorted off the field Friday night by Mets manager Terry Collins and trainer Ray Ramirez, a segment of fans booed the left fielder, who has not lived up to his four-year, $66 million contract.
That raised the ire of reliever Jon Rauch among others in the Mets clubhouse.
Rauch took to Twitter and wrote: "Very disappointed with the fans who booed Jason Bay as he came off the field. This is a serious injury that affects his livelihood and his well being. He plays his heart out every time he takes the field. It's very unfortunate that he's had to deal with multiple concussions and other injuries -- we all have him and his family in our thoughts and prayers for a speedy recovery."
Bay missed the final two months of 2010 after suffering a concussion. This season, he has been limited to 21 games because of a fractured rib. He has been back for just seven games since that injury.
"Since he has had it in the past, this becomes a pretty serious thing," Collins said after his team's 7-3 loss to the Reds.
Bay, 33, has had a woeful time since leaving the Red Sox and signing with the Mets. Brought in mostly for his power, he has hit a total of 22 home runs after nearly 2½ seasons.
"I felt terrible for Jason," Collins said. "He always plays the game one way -- all out. He never backed off anything. He didn't back off the wall. He didn't back off a broken rib. He still dove. He still plays the game the only way he knows how."
When Collins went out to check on Bay after the fall, Bay told him he was dizzy, but that he wanted to remain in the game.
"I said, 'Not with the past,' " Collins said, referring to the 2010 concussion.
Scott Hairston replaced Bay in left.
In Bay's place, Hairston will receive more playing time, but Kirk Nieuwenhuis likely will receive the bulk of the action.
"I haven't figured that out yet," Collins said.
Both Hairston and Nieuwenhuis hit home runs on Friday.
Bay is hitting .187 with four homers and six RBIs this season. He is due to make $16 million next year, the last of the contract.
He has a vesting option of $17 million for 2014 if he is able to have 500 at-bats this season and next, or 600 in 2013. If he doesn't reach either incentive, the Mets will have the option to buy out Bay for $3 million.
"It didn't matter what he did, if he didn't hit 40 homers, he wasn't going to be the same guy everyone thought he was going to be," Collins said. "It didn't matter how he played the game. It didn't matter anything else. He had to be a home run hitter. Jason Bay is a fine baseball player. When you hit 45 home runs, you get paid.
"That is the nature of the game. It doesn't mean he has to hit 45 every year, but that is expectation. Jason Bay is one of the finest people that I've ever had on my team. I just hope he gets out of this and recovers, because I'm pretty concerned about it right now."
Bay did not talk to reporters, having left for home during the game.
Info from ESPNNewYork.com's Adam Rubin was used in this report.