Source: Third Baseman Adrian Beltre on Red Sox’ Radar

With Mike Lowell's declining mobility apparently a concern for the Red Sox brass, multiple sources have told the Boston Herald that the club is showing "significant" interest in free-agent third baseman Adrian Beltre of the Mariners.

With rumors swirling that Boston is shopping the aging Lowell this offseason, Beltre would appear to be the best choice to fill the void at the hot corner should Lowell be shipped away.

The 12-year veteran third baseman has a .270 career batting average but struggled mightily this past summer with the Mariners, belting just eight homers and driving in 44 runs in 111 games. These stats are a far cry from his regular numbers as the 5-foot-11, 170-pound Dominican native averages over 24 homers and 80 RBIs per season and even smacked 48 long balls and drove in 121 runs in a career year back in 2004 with the Dodgers.

Beltre, who will be 31 in April, is coming off a five-year deal that paid him $12.4 million per season. Sources are telling the Herald that despite his decline last season, he is still seeking another long-term deal with an annual salary of at least $13 million.