The Boston Red Sox enter the final phase of spring training lacking the solidity that characterizes a pennant-winning club.

Yesterday the Sox lost 4-3 in 12 innings to the Minnesota Twins, dropping their spring record to 6-11 for ninth place in the American half of the Grapefruit League so far.

The pitching staff is the biggest question mark. Jim Lonborg, who had a 22-9 record last year, is out of the line-up with a knee injury at least until May.

The rest of the Sox's starters have been erratic. Jose Santiago and Gary Waslewski have been slow to develop, and Ray Culp and Dick Ellsworth, acquired in trades over the winter, have ranged from great to terrible.

Culp went six innings Sunday in the Sox' 6-2 victory over the Braves and gave up only one earned run.

Slump

The team batting average this spring is down to .235 from last year's .225 season mark.

Triple crown winner Carl Yastrzemski and Tony Conigliaro, who sat out the latter part of the season after being seriously injured by a wild pitch, have both dropped off from their last season averages.

The Red Sox are getting unexpected strength from Jose Tartabull and several infielders, including Joe Foy, Ken Harrelson, and Mike Andrews.

The infield has tightened up into a solid defensive unit. A slimmed-down Joe Foy has picked up his defensive play at third base, and the double play combination of Rico Petrocelli at shortstop and Andrews at second has been one of the bright spots all spring.