BOSTON (AP) -- Boston starter Jon Lester is running low on patience as well as solutions to whatever has been troubling him this season.
Lester's struggles continued in a 7-5 loss to the Chicago White Sox on Tuesday night, when he allowed six runs in four innings, including a three-run homer to former teammate Kevin Youkilis.
Lester threw 50 pitches in the first two inning, falling behind 2-0 in the first and then 3-2 in the second.
"I don't think there's anything else I can work on. I've worked on everything. Just come game time, I've got to throw the ball better. Just plain and simple," Lester said. "Guys did a great job in that first inning of picking me up and I didn't pick them right back out."
It was the third time this season Lester (6-6) has allowed six or more runs.
Although his pitch count was high, he was still in contention for the win in the fourth when Youkilis, traded less than a month ago to Chicago, hit a 3-2 pitch over the Green Monster with two men on. Lester had fallen behind Youkilis 3-0 and after getting two strikes, put one right where the former Red Sox slugger could power it.
"Youk's a good hitter," Lester said. "We've all seen him for a long time do what he did."
The White Sox won for the eighth time in 11 games and are 10 games above .500 (50-40) for the fourth time this season.
Philip Humber (4-4) made his first start in a month and settled down after allowing two runs in a shaky first inning, when the Red Sox tagged him for three hits and two runs to tie it after Chicago went up 2-0 in the top of the first.
Humber had been on the disabled list as he recovered from a right elbow strain. Chicago activated him earlier Tuesday and he gave the White Sox six strong innings, scattering six hits, striking out three and not walking a batter before leaving the game after throwing 104 pitches.
Kelly Shoppach had a pinch-hit, two-run homer in the eighth for the Red Sox off Matt Thornton to pull Boston to 7-5, but closer Addison Reed came on in the ninth and picked up his 15th save.
Carl Crawford continued his strong start since joining the Red Sox on Monday after rehabilitating wrist and elbow injuries during the first half of the season. Crawford went 3 for 4, stole three bases and scored twice on Tuesday. In two games back, Crawford is 4 for 7 with four runs scored.
Lester had good velocity, but poor control from the start. He threw 27 pitches in the first when Youkilis walked and Adam Dunn, Paul Konerko and Alex Rios followed with hits to put the White Sox up 2-0.
Crawford and Adrian Gonzalez hit RBI singles to tie it in the bottom of the first, but Chicago went up in the second with a run, then Youkilis blew it open in the fourth.
"It was a frustrating night for Jon," Boston manager Bobby Valentine said. "After he gave up the two in the first and we came back, he thought he'd be able to settle down and get us the victory. His control just wasn't there."
With two on and two outs, Youkilis hit a towering shot to left to put the White Sox up 6-2 in the fourth. Boston fans cheered "Yooouk!" as he trotted around the bases, showing the former Red Sox third baseman will always be beloved in Boston.
It was Youkilis' fourth homer since being traded from to Chicago, tying his total with the Red Sox in 42 games this season.
"You never know here, but it's been great," Youkilis said of his reception. "Fans have treated me unbelievable and I can't thank them enough for all the kind things they keep saying from the stands every day and every inning. Not too many opponents get to come in here and have that opportunity. Usually it's a little more negative at the opposition."
Lester allowed six runs on seven hits over four innings.