TORONTO -- Farrell has been impressed with Mookie Betts, who, in his third stint with the Sox, has shown more discipline at the plate and surer instincts in the outfield.
He's hit safely in his last five games and since returning to the big leagues on Aug. 18, he's amassed twice as many walks (eight) as strikeouts (four). His on-base percentage in that span is .421.
"Clearly, on defense, his reads and his routes are more specific,'' said Farrell, "particularly going back on balls. As he's gotten accustomed to balls being driven a little bit more regularly, that's an adjustment that's happened naturally. And with each game played, his confidence has grown -- (in instances like) when to steal a base.
"But the one thing that's been consistent in three times he's been with us is the way he's managed his at-bats. You look at an even strikeout-to-walk rate for a young guy, I think is extremely impressive, (even in) the short number of at-bats he's had.''
Will Middlebrooks continues to struggle. He was 1-for-10 with seven strikeouts in the first two games and often seems to be caught in-between at the plate.
"At times, he's taken a number of (called) strike threes,'' said Farrell, "like he's in a little bit of a survival mode. There's an approach that he's trying to blend -- being patient and not expanding the strike zone. Whether or not that gets into anticipating one pitch and not another....that's where I think some of those called looking have come into play.''
Rosters can expand to 40 players Monday Sept. 1, but with Triple A Pawtucket set to take part in the International League playoffs, the Sox don't want to make too many callups until after their affiliate's season is over.
"I think what we'll look to do is call up some pitching initially,'' said Farrell. "We'll (wait) on the others until they get through their playoff run.''
Expected to join the Sox Monday will be Dan Butler, who will give the Sox a third catcher for flexibility and pitchers Steven Wright and Brandon Workman.
Matt Barnes would be another candidate, but he's not on the 40-man roster, which is currently full. The Sox could create room easily enough, however, by transferring Shane Victorino (back) from the 15-day DL to the 60-day DL.
"We're balancing guys currently in the rotation getting to an innings threshold,'' said Farrell, "and the need for multi-inning guys behind them is there.''