According to Pat Borzi of the New York Times, Terry Collins believes the two concussions Jason Bay has sustained during his tenure with the Mets have contributed to his declining production at the plate.

“I don’t know; I’m just trying to guess,” Collins said, according to Borzi. “There’s got to be something that’s keeping him from being the hitter that he was a few years ago. The only thing you can point to are the injuries.”

Meanwhile, Bay isn’t sure the concussions are the culprit, saying:

“Terry’s asked me that, and I have nothing to quantify that with. How do you know? I don’t feel like it has. A lot of people look for a lot of reasons as to why things may or may not have come down as they historically have. Albeit that’s a viable scenario, but I can’t tell you from one day to the next how it felt. Those things did occur, but if I knew the answer, I would have fixed it by now.”

Bay is hitting .156 with seven home runs and 18 RBI with 54 strikeouts in 179 at-bats this season. The .156 average is the lowest mark among players with at least 100 at-bats in the Major Leagues.

Michael Baron, MetsBlog.com:

 I buy into the notion the concussions have taken their toll on Bay and that along with other injuries have negatively impacted his ability to adjust and evolve into a different kind of offensive player. The thing is, it’s just not there with Bay anymore, and it hasn’t been there since he joined the Mets in 2010. As a result, I don’t know if it’s fair to blame all of his problems solely on his injuries.

I talked with Bay during his rehab from the latest concussion, and he said he actually felt better after this one than the one he had two years ago in Los Angeles. He felt that was a product of experience with concussions in that he knew how to manage the symptoms. But he also talked about how hard he’s worked to try and find some consistency, and how he has worked regularly with the coaching staff on it as well. In watching him on the field, it’s clear his struggles aren’t attributable to a lack of effort, and I appreciate the fact he’s honest about his problems. There are a number of occasions when Bay could’ve taken the easy way out, and blamed one thing or another on his lack of production, and he never has. Instead, he has been completely up front about his problems and shown genuine frustration about not positively contributing. There have been plenty of players who have underperformed over the years who have sounded indifferent about their issues – Bay is definitely not one of those guys, and I appreciate that very much as a fan.

Bay is finishing the third year of a four-year, $66 million contract he signed before the 2010 season. He will earn $16 million in 2013 and the Mets hold a $17 million club option on Bay for 2014 with a $3 million buyout – at a minimum, the Mets will owe Bay $19 million through the remainder of the deal.

Since joining the Mets for the 2010 season, Bay has hit .234 with 25 home runs and 122 RBI in 971 at-bats over 281 games. He has not played in more than 123 games in any season with the Mets.