Jed Lowrie shows his true potential

BOSTON -- When Jed Lowrie stomped on home plate Saturday night, he was bombarded by his Boston Red Sox teammates. He had just hit a walk-off home run to lead off the bottom of the 11th inning, giving the Red Sox a 5-4 victory over the Toronto Blue Jays at Fenway Park.

As the ball sailed into Boston's bullpen in right-center field and Lowrie rounded the bases, it was one of the best moments he's had on the diamond in more than two years.

When the Red Sox broke camp this past spring training in Fort Myers and returned to Fenway Park to begin the season, Lowrie remained in Florida to deal with a serious bout of mononucleosis.

After he was diagnosed and placed on the disabled list March 31, the illness ravaged his 26-year-old body to a point where he spent close to 20 hours a day resting and sleeping. In fact, during the first three weeks, he would wake up, report to the ballpark then go home and get right back into bed.

"I was showing them I was alive," Lowrie said.

Mentally and physically, he didn't know what to expect moving forward. It seemed like every time he had been given an opportunity, something would happen to deprive him of a big league career.

While he remained in Florida, Lowrie wasn't thinking about playing baseball. He wanted only to be healthy.

"I knew in my heart that I would play again, but I wasn't focused on it at that time," he said. "I didn't know what to expect. At the time I knew how I felt, and for a lot of it, it wasn't very good. I really didn't know if I would play this year. It feels good to be back."

Lowrie was activated from the disabled list July 21 in Oakland, and since he's returned is hitting .317 with three homers and eight RBIs. He's riding a career-high nine-game hitting streak.

He has come back in a big way for the Red Sox, and he proved it again Saturday night.

Lowrie wasn't in the starting lineup against the Blue Jays, but he was inserted as a pinch-hitter in the bottom of the eighth inning with the game knotted 4-4. He drew a walk but was left stranded.

As the game went into extra innings, Lowrie remained at first base, a position he's started to play only recently. With two outs in the top of the 11th inning, the Blue Jays' John Buck lifted a high fly ball in foul territory in front of the Red Sox dugout. Lowrie positioned himself perfectly underneath it, but the ball hit his glove and dropped.

Red Sox closer Jonathan Papelbon eventually struck out Buck to end the inning.

Lowrie said he was hoping Papelbon would pick him up and register the third out of the inning, especially given the fact Lowrie would have a chance to redeem himself by leading off the bottom of the inning.

He capitalized on his chance.

It was Lowrie's first career walk-off homer and, believe it or not, the first of the season for the Sox.

"It's funny how the game works out like that," Lowrie said. "Fortunately, the error didn't matter. I got the opportunity to lead off the inning and end the game.

"I put a good swing on it and it went out. I knew I hit it well, but it's a long ways out there at Fenway. I knew I hit it well and I was just watching [Jose] Bautista run after it, hoping it would keep going."

It's the third time in Lowrie's career that he's provided a walk-off hit, including a 12th-inning single against the Athletics in a 2-1 win Aug. 1, 2008. His most memorable, however, came in Game 4 of the 2008 ALDS when his single in the bottom of the ninth inning gave the Sox a 3-2 victory and clinched the series over the Angels.

Saturday's heroics were a close second.

"They're both walk-offs, but the magnitude of a playoff game, it overshadows it a little bit -- especially what I went through that year, playing with a broken wrist. That moment overshadowed this one a little bit, but that's not to say this one wasn't exciting."

Lowrie has battled nothing but adversity in an attempt to become a fulltime major leaguer.

He made his big league debut April 15, 2008 and spent the first month of the season with the Red Sox before being optioned to Triple-A Pawtucket on May 11, 2008. He was recalled that July and started 57 of the club's final 64 games after then-Red Sox shortstop Julio Lugo went on the DL.

Lowrie played the majority of the 2008 season with a non-displaced fracture in his left wrist and was limited to 32 games in 2009 after needing surgery to repair the damage. Then this spring, he was dealt another blow when he was diagnosed with mono.

The Red Sox have yet to witness what a healthy Jed Lowrie can do at the plate and in field at this level. With all the contributions, and the way he's been playing since being activated, it appears they are finally seeing it.

"He can do that, we've just got to keep him healthy," said Red Sox manager Terry Francona.

When Lowrie realized the ball had carried over the wall, giving the Red Sox a much-needed win, he yelled a celebratory expletive as he began his home-run trot.

"Jumping on the plate is a pretty incredible feeling," Lowrie said.

Joe McDonald covers the Red Sox and Bruins for ESPNBoston.com. Follow him on Twitter.