Blue Jays fans can point to several reasons why their third-place club is 31-23 since May 10 and feeling alive and well in the Wild Card picture midway through July.

More and more, they've tapped into Alex Rios' bat as an emerging power source. They've resuscitated Frank Thomas and Vernon Wells after slow starts. And they've seen Matt Stairs emerge as a offensive threat off the bench.

But Shaun Marcum, who starts on Friday at Fenway Park, has been the man holding together a pitching staff marred by injury and underperformance. The Jays can only hope that his Saturday start against the Indians, in which he was touched for eight runs in just 3 1/3 innings, remains a temporary blight on a so-far sterling record.

What's next for Marcum? The 25-year-old right-hander has been the team's most effective starter since his inclusion in the rotation on May 19, when he held the Phillies hitless for six innings.

Before Saturday, Marcum had lowered his ERA from 6.06 to 2.86 in his time as a starter. Including the shelling by Cleveland, Marcum has held batters to a .221 average, striking out 68 in 82 innings.

If he cuts down on long balls and manages to repeat recent history (he has fared well against his Friday opponent), Marcum can return to the fast track against the mighty Red Sox.

Pitching matchup
TOR: RHP Shaun Marcum (4-3, 3.62 ERA)
Marcum has allowed just nine hits and three earned runs in 15 innings against the Red Sox, mostly as a reliever. In his one start against Boston, on Sept. 25, 2006, Marcum shut out the Sox for eight dominant innings, allowing two hits and striking out 10. He has never started at Fenway Park.

BOS: RHP Julian Tavarez (5-7, 4.97 ERA)
Like Marcum, Tavarez has been a Jekyll-and-Hyde figure in recent weeks. Like Marcum, the 34-year-old Red Sox starter solidified his spot in the rotation by pitching brilliantly through late May and June. And like Marcum, Tavarez was shelled by the Tigers in his last outing. Tavarez has a 4.57 ERA against the Blue Jays in 43 1/3 career innings.

Players to watch
Outfielders Vernon Wells and Alex Rios have thrived against Tavarez, combining to bat .600 (15-for-25) with six extra-base hits against him, two of them home runs.

Tickets
 Buy tickets now to catch the game in person.

On the Internet
 MLB.TV
 Gameday Audio
•  Gameday
•  Official game notes

On television
• RSN

On radio
• FAN 590

Up next
• Saturday: Blue Jays (Dustin McGowan, 5-4, 4.65) at Red Sox (Daisuke Matsuzaka, 10-6, 3.84), 7:05 p.m. ET
• Sunday: Blue Jays (Jesse Litsch, 1-3, 4.74) at Red Sox (Josh Beckett, 12-2, 3.44), 2:05 p.m. ET
• Monday: Blue Jays (Josh Towers, 4-5, 5.07) at Yankees (Kei Igawa, 2-2, 7.14), 7:05 p.m. ET