A second member of the New York Yankees' rotation has tested positive for COVID-19.
Boone said "as of now" it's just the two pitchers who have tested positive and no other players are unavailable due to contact tracing.
Cole, who was scheduled to start Tuesday night's game against the Baltimore Orioles, was replaced by top prospect Luis Gil, who made his major league debut in the Yankees' 13-1 win. Montgomery had been slated to pitch next on Friday.
Both Montgomery and Cole will likely be sidelined at least 10 days from the date of their positive test under MLB's protocols.
"Yeah 10 days, I believe, it'll be 10 days unless they test negative on multiple occasions prior to that, then they can come back sooner," general manager Brian Cashman said in an interview with WFAN radio, according to SNY. "And on top of that it could be longer because then you got to make sure their arm care is good and what kind of position can they do work in while they're remote."
At least 85% of New York's players are vaccinated. Boone said he believes it's up to the players to decide whether they want the COVID-19 vaccine.
"I think the right thing to do is to be vaccinated,'' Boone said. "I've said that a number of times, but in the end it's up to individuals.''
Earlier this month, star slugger Aaron Judge was among six Yankees players who tested positive for coronavirus.
Montgomery, 28, is 4-5 with a 3.69 ERA in 21 starts this season. His most recent start was Sunday, when he had a no-decision in a 3-1 win over Miami.
The Associated Press contributed to this report.