Middlebrooks has been called up and will immediately be inserted into the starting lineup Wednesday night against Oakland, manager Bobby Valentine said on a Boston radio spot (via MLB.com). Lars Anderson has been optioned to Triple-A Pawtucket as a corresponding move.
Should Youkilis need a DL-stint, Middlebrooks will certainly be activated and probably start playing on an everyday basis. (UPDATE: Yes, Youkilis is hitting the DL, so it's Middlebrooks' time to shine)
Middlebrooks, 23, was hitting .333/.380/.677 with nine homers, 27 RBI and 18 runs in 24 Triple-A games this season. He was ranked as one of the Red Sox top prospects and in the top 60 in all of baseball by most outlets before the season. His hot hitting to start the season only increased his stock.
Middlebrooks and the Red Sox face Brandon McCarthy and the A's at home Wednesday night.