Recovering from a back injury, Middlebrooks homered for the second time in three games Thursday. His homer was the only hit of the night in four at-bats, but he is 4-for-9 with two homers and six RBIs in his three rehab games.
"Very encouraging," Farrell said Thursday afternoon. "Some of the things that we've highlighted with Will, he showed [Wednesday]. Obviously with the home run to right-center field. And as we stated before, when he's in the right place, doing what he's capable of, he's proven he's a Major League player.
"A right-handed bat that's potent, has the potential to be potent and has showed it throughout most of the time last year, and there was obviously inconsistencies here throughout this year, but like I said, I think it's important to be able to use this time and this opportunity to get some momentum going before he comes to us."
Middlebrooks, who hit .201 in 46 games before going on the disabled list, could return to Boston's roster Saturday against the Angels at Fenway Park.
Shane Victorino, who has dealt with a back injury and a hamstring strain, made his first rehab start Thursday and also went deep. He finished 2-for-4 with a home run and a strikeout. Victorino was batting .283 before going on the DL.
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. Michael Periatt is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.