Shawn Tolleson unavailable Sunday; status unclear going forward

The Dallas Morning News

Texas Rangers relief pitcher Shawn Tolleson pitches during the ninth inning against the New York Yankees at Globe Life Park on Wednesday, April 27, 2016, in Arlington. (Smiley N. Pool/The Dallas Morning News)

ARLINGTON - Before manager Jeff Banister decides whether to "unplug" Shawn Tolleson from the closer's role or roll with the status quo, the Rangers engage in a little forensic baseball.

In short, the club is trying to determine what has happened to his changeup, the pitch that vaulted him from set-up man into unlikely, but spectacular, closer in 2015. In the small six-week sample at their disposal, the Rangers believe batters are having better success against the…