Justin Morneau's latest concussion has him rethinking his future as a ballplayer.

No, the 30-year-old isn't contemplating retirement. But as much as he loves playing first base, his main priority is becoming a season-long mainstay in the Twins lineup, even if that means more time at designated hitter.

"If that's something I need to do, and if that means being able to hit fourth and help this team win every day, I'll do it," he said. "The last thing we need is to be out there tentative, and not being able to play the game the way it's supposed to be played."

Morneau's awakening came Aug. 28, when he began feeling concussion symptoms after diving awkwardly for a double down the first-base line by Detroit's Alex Avila.

Morneau's previous two concussions came on blows to the head. On April 6, 2005, he got beaned by Seattle's Ron Villone. On July 7, 2010, Morneau got kneed in the head by Toronto's John McDonald while trying to break up a double play.

"That's kind of what makes this whole thing scary," Morneau said, "It's a simple play, diving for a ball, that brought this stuff back again. So I don't know."

Morneau missed the final 78 games last season and has missed 14 games -- and counting -- since leaving the lineup Aug. 28.

With the symptoms lingering, Morneau has kept in regular contact with Dr. Michael Collins, the Pittsburgh concussion specialist who is treating concussed NHL star Sidney Crosby as well as Twins center fielder Denard Span.

Morneau, who is married with an 11-month-old daughter, said he thinks about the long-term effects these concussions could have on his brain.

"That's one of those concerns for sure," he said, adding that it might be time for another round of extensive tests. "I think that's something we'll revisit this winter, if not the next couple weeks, if this stuff continues. You never know. You put your trust in people who have experience who have studied this stuff their whole life and hope they're right."

Another painful season

This whole season has been a tremendous struggle for Morneau. Recovering from last year's concussion limited his offseason workouts. He missed more than half of spring training and never found his groove.

Even though his concussion issues were seemingly behind him, new problems arose. A pinched nerve in his neck began causing numbness in his left finger and weakness in his left arm. Then he strained his left wrist.

With teammates dropping like flies, Morneau fought to stay off the disabled list, but he had trouble swinging with one good arm. By mid-June, he was back on the DL, right where he had ended the 2009 and 2010 seasons.

His wrist healed in a cast, and he had surgery to relieve the pinched nerve. After missing 55 games, he returned for 14 games in August, showing only flashes of his old brilliance.

Technically, Morneau is not on the DL now, because major league teams can expand their active rosters to 40 players in September. But it's uncertain whether he will play again this season, and if he does, Twins manager Ron Gardenhire has said it will be as a DH.

Minnesota native Eric Nauman, an associate professor of mechanical engineering at Purdue and an expert in the central nervous system and musculoskeletal trauma, has followed Morneau's concussion issues from afar and said he would have concerns moving forward.

"If he was feeling bad after falling down like that, or diving, I would be worried about it, to be perfectly honest,'' said Nauman, part of a Purdue team of researchers that recently completed a two-year study on head injuries. "Speaking as a mechanical engineer who studies a lot of biological structures, I've seen damage in all kinds of forms, and I would definitely be worried about him.''

Morneau is batting .227 with four home runs and 30 RBI in 69 games. With Joe Mauer, 28, struggling through his own injuries -- batting .287 with three homers and 30 RBI in 82 games -- Twins fans can't help but wonder if these former American League MVPs will ever be the same.

"It was only last year that both of us were supposed to be starting in the All-Star Game," Morneau said. "So it's not like it was four or five years ago. There's no reason we can't get back to that point."

Looking forward to 2012

Mauer has played his first 18 career games at first base this season, filling in for Morneau, which gives the Twins more options moving forward.

"Whatever gives us the best chance to win," Morneau said. "If that's me playing first and him catching -- that's kind of why we're both signed here. But we need [Mauer's] bat in the lineup as much as we can. If that means him playing first base once a week, or whatever, let me DH."

After this season, Morneau will have two years left on his six-year, $80 million contract. Mauer is signed through 2018, at $23 million per year. Of all the problems that have been exposed this year, with the Twins at 59-89, their other concerns pale in importance to Mauer and Morneau.