Right fielder Shane Victorino left Wednesday's 6-5 Red Sox win over the Athletics after the sixth inning with a sore lower back, the same injury that caused him to miss two games over the weekend. Victorino barely jogged to first when he grounded out in the sixth. He was working with physical therapist Dan Dyrek on his back before the game and was 1 for 3 with an RBI double before aggravating the injury. Manager John Farrell said Victorino’s back tightened up but did not seem as bad as it was previously. He will be evaluated again Thursday. Also: • Jon Lester is 4-0. He didn't win his fourth game until June 16 last season. The Sox are 9-0 in games started by Lester and Clay Buchholz. The duo is 8-0 with a 1.61 ERA • David Ortiz has an unusual 16-game hitting streak, his longest as a member of the Red Sox. It started in July, included one game in August, and now has gone four games in April. He is 8 of 16 since coming off the disabled list. • Jacoby Ellsbury is 10 for 10 on stolen bases in 21 games. He had 14 in 74 games last season.