Elvis Andrus will be locked up for at least the next six years, but could be playing shortstop for the Texas Rangers until 2022, after agreeing to an eight-year, $120 million contract extension that will begin when his current deal expires in 2014.The deal, which includes a $2 million signing bonus, features an opt-out clause that would allow Andrus to become a free agent four years into the extension. A source said late Sunday that the Andrus camp is uncomfortable with the thought of him playing out the full length of the deal and becoming a free agent at age 34 after 14 major-league seasons.Andrus is to undergo a physical examination Monday as the final step before the deal becomes official, according to another source. A third source said that, as of Monday morning, the Rangers were not planning to announce the deal Monday.Andrus will become the fourth-highest paid shortstop in the league once the deal is finalized. His long-term presence in the Rangers' infield brings into question the futures of second baseman Ian Kinsler and top prospect Jurickson Profar.Kinsler is in the first year of a five-year, $80 million contract, and he balked at a move to first base in the off-season so soon into his new deal. The Rangers could have outfielders David Murphy and Nelson Cruz hit free agency after this season, so Kinsler could be asked to replace either one of them.The Rangers could also use Profar as the centerpiece in a trade for All-Star outfielder Giancarlo Stanton or 2012 Cy Young winner David Price, both of whom are expected to be available as their free agency approaches.