"We still have to wait on things before making the final call on that," Washington said on Monday.
Holland will be replacing Rich Harden in the rotation, with Tommy Hunter moving up one day to start on Tuesday. Hunter will pitch on three days' rest after being limited to three innings and 50 pitches in his most recent start on Friday during the Rangers' 10-9 walk-off win over the Red Sox in 11 innings.
"[Hunter] threw a bullpen yesterday and things went well, and we thought it worked well with him going on Tuesday as opposed to Wednesday," Washington said. "He only threw 50 pitches and he's pitched well this season, and we felt it was the best to go with him after seeing him toss his bullpen session."
Holland, who is 6-2 with a 1.91 ERA in 10 starts with Triple-A Oklahoma City, lasted just 2 1/3 innings in his last start on Friday against Las Vegas. Holland threw 59 pitches while allowing three runs. He is 2-1 with a 4.19 ERA in four starts and one relief appearance at the Major League level this season.
"He's been dominating pretty much every start up until his last one," Washington said. "No one can dominate every game. Sometimes there's going to be one or two which gets away, but for the most part, he's been solid."
Harden was placed on the 15-day DL on Sunday, retroactive to Aug. 8, with right shoulder tendinitis. The 28-year-old right-hander is scheduled to make a rehab start for Oklahoma City on Tuesday against Reno.
Harden had made just two starts since coming off his last stint on the disabled list with a strained lower back muscle. He lasted just 2 1/3 innings in his last start against the Athletics on Aug. 7, giving up three runs and throwing 65 pitches.