It was a question that had to be asked of Red Sox relief pitcher Andrew Miller. What’s with all the hair? The lefthander looks like a cleaner — and taller — version of the character Tom Hanks played in the film “Castaway.” Miller has shoulder-length hair and a bushy beard that hasn’t seen scissors in many months. “It just kind of happened. I have no idea why,” Miller said Tuesday. “I’m holding strong against my wife, I guess is what it is.” Katie Miller may have her way soon. Miller admits he needs a trim “pretty badly” and may get it done before the season. “One of these days I’ll come in and it’ll be cleaned up a little bit,” he said. Clean-cut manager John Farrell, who joked that conversations take place regarding Miller’s wild-man look, doesn’t want to change much else about the pitcher. After a series of fruitless seasons in the majors, Miller was consistently effective last year. Miller appeared in 53 games and had a 1.19 WHIP over 40⅓ innings with 51 strikeouts and 20 walks. Lefthanders hit .149 against him with a .429 OPS. At 27, Miller has found a role as a situational reliever after trying, and failing, in other roles. The Tigers thought Miller would be a dominant starter when they selected him with the sixth overall pick of the 2006 draft. But he was rushed to the majors, struggled, and was one of six players traded to the Marlins for Miguel Cabrera and Dontrelle Willis before the 2008 season. Miller spent three frustrating years with the Marlins, getting hit hard as a starter and reliever, with occasional demotions to the minors. The Red Sox acquired him at a discount rate before the 2011 season, sending the Marlins lefthanded reliever Dustin Richardson. Miller started 12 games for the Sox in his first season in Boston after beginning the year in Triple A Pawtucket. He was hit hard again before the Red Sox tried Miller out as a specialist last season.