This is probably no big deal -- it could be just spring soreness that can be dealt with through rest. And Elvis is someone who plays through pain, so even if it is bothering him during the season, if it is something he can play through, he most likely will.
However, lingering arm soreness -- and particularly forearm soreness -- is always worrisome, since it raises the specter of a possible damaged elbow ligament. And in that sort of worst case scenario, we would be looking at Elvis likely being done for the season.
While this is hopefully nothing, its at least worth considering what the Rangers would do if Elvis were to miss a significant chunk of the season. Jurickson Profar is perfectly capable of playing shortstop, and while the Rangers wouldn't want to move him over there for just a short term fix, if Elvis were to miss months or a full season, Profar to shortstop might be the Rangers' best option, as he's probably the best defensive shortstop who would be an option for the major league roster.
That would mean the Rangers would potentially look at Adam Rosales, Kevin Kouzmanoff or Brent Lillibridge as their every day option at second base. None of those, of course, are attractive options.
Alternatively, the Rangers could turn to Rougned Odor. He just turned 20, he only has 30 games above A ball, and he's not on the 40 man roster, but he might be the team's best option as a full-time major league second baseman if Profar were to go to shortstop.
Finally, Stephen Drew is still out there on the market. While Drew supposedly wants a long-term deal, if the Rangers decide they need a one-year patch at shortstop in a worst-case scenario, he's out there, and the Rangers have shown a willingness to play ball with Scott Boras clients before.