"He is going to continue to get treatment today," Rangers manager Jeff Banister said. "If it's a situation where it doesn't get any better, we'll probably have him checked out on the off-day [on Monday] and then see how he comes back after the off-day."
The Rangers are off Monday, play two home games against the Mets, have one more day off on Thursday and then play three games against the Nationals in Washington.
The designated hitter won't be used during those games in D.C. The Rangers might be able to hold off putting Napoli on the disabled list through the two games with the Mets, but they don't want to be caught short on the bench playing against the Nationals under National League rules.
Ronald Guzman is playing first base at Triple-A Round Rock and entered Sunday hitting .294 with five home runs, 23 RBIs and a .426 slugging percentage. But the Rangers have Joey Gallo to play first base at the Major League level while Napoli is down, so utility player Drew Robinson might make more sense if there is a roster move.