Lee paced the NL by hitting .550 (11-for-20), tallying three home runs, two doubles and 11 RBIs to earn the honor for the first time in three years.
His week -- and likely his season -- ended prematurely after a Bronson Arroyo pitch broke his left pinky finger on Saturday. The Astros placed Lee on the disabled list for the first time in his career, and are expecting him to miss six to eight weeks. Lee was hitting .314 with 28 homers and 100 RBIs in 115 games before the injury.
"I've never felt this good in my career at the plate," said Lee on Monday. "I believed I was going to help [the team] to make a comeback and do the best for the team but now, I'm out."
The Astros went 5-2 last week, including a four-game sweep at Cincinnati. As of Monday, Houston was in fourth place in the NL Central, 12 1/2 games behind Chicago and 8 1/2 back in the Wild Card race.
Lee did his best to help Houston gain ground on the division-leading Cubs early last week, going 4-for-12 with two home runs and six RBIs. He was even better against the Reds before going down. Lee went 3-for-3 on Thursday and 4-for-5 on Friday. Lee reached base 12 times in 13 plate appearances in that series.
As All-Star first baseman Lance Berkman came back to Earth, Lee had picked up his production since the All-Star break. He had four straight multi-RBI games last week. Now, Berkman and Co. must move on without their slugging left fielder.
"With men in scoring position, Lee's just been an awesome player, getting big hit after big hit," Astros manager Cecil Cooper said. "He's carried us over the last month and a half or so with home runs, base hits, and he's played terrific defensively. It's a big hole to fill."
Lee previously won player of the week on May 8, 2005, when he was with the Brewers.
Other nominees for this week's honors included fellow Astros Kazuo Matsui (.333 average, one home run, three RBIs) and Brian Moehler (2-0. 0.75 ERA, seven strikeouts).
For his efforts, Lee will receive an engraved luxury Swiss Tourneau timepiece.
Nick Zaccardi is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.