One of the few concerns currently facing the surging Chicago White Sox is the performance of Philip Humber.

Still searching for his first victory since pitching a perfect game more than a month ago, Humber tries to help the White Sox extend their longest winning streak of the season to seven games Tuesday night against the Tampa Bay Rays at Tropicana Field.

While Chicago (27-22) has won 10 of 11 to move within one-half game of first-place Cleveland in the AL Central, Humber (1-2, 5.80 ERA) has struggled to sustain any kind of success since throwing the 21st perfect game in major league history April 21 at Seattle. Since that achievement, the right-hander is 0-2 with an 8.22 ERA in six starts.

Humber gave up three runs over 13 innings spanning two solid starts, but then allowed five runs Thursday in 4 1/3 innings of Chicago's 11-8 win over Minnesota.

"I haven't felt like I've really been in sync probably for awhile now," Humber said. "I've got to figure out what's going on. There's a lot of feel that goes on as a pitcher."

The right-hander went 1-1 with a 3.97 ERA against the Rays last season.

Chicago had averaged 10.4 runs in its previous five games, but needed only a two-run homer from Adam Dunn and a 15-strikeout performance over 7 1/3 innings from Chris Sale to win 2-1 at Tampa Bay on Monday.

The White Sox are trying to win seven in a row for the first time since Aug. 30-Sept. 6, 2010.

Dunn, who had 11 homers during a disappointing 2011, has 11 this month alone and 16 on the season.

"You get some guys on and he can do a lot of damage," manager Robin Ventura said of Dunn, whose 37 RBIs are five fewer than his 2011 total.

He has a chance to homer in four straight road games for the first time since Aug. 4-7, 2004, while with Cincinnati.

Teammate Paul Konerko went 1 for 4 to extend his hitting streak to 14 games. Batting .395 on the season, Konerko has hit .540 (27 for 50) during the streak. He's batting .415 in his last 11 games versus Tampa Bay, but is 5 for 23 with no extra-base hits against Tuesday's scheduled starter James Shields (6-2, 3.63).

The right-hander is 0-1 with a 4.05 ERA in his last two home starts after going 8-0 with a 2.48 ERA in his previous 10 outings at Tropicana Field. He allowed three runs and struck out 10 in 7 1/3 innings of a 5-4, 11-inning win over Toronto on Wednesday.

Shields is 4-2 with a 4.66 ERA in 10 starts versus the White Sox including postseason. He gave up four hits during a complete-game 2-1 home victory in his last outing against them April 19, 2011.

Ben Zobrist had two of the three hits Monday for the Rays (29-20), who failed to earn a fifth win in six games. Zobrist is batting .213 this season, but .350 with four homers and 10 RBIs in 12 career home games against the White Sox.

Copyright by STATS LLC and The Associated Press