Huth has struggled to get into the Stoke first team this season after a long spell on the sidelines with a knee injury, but injuries to other defenders has reportedly put the decision to let him leave for Leicester under the spotlight.
In an interview with the Stoke Sentinel, Coates explained Mark Hughes and the rest of the first team staff felt he needed some game time at higher level than with the under-21 side in order to recover from a long-term knee injury.
He said: "Yes, I can understand why supporters would be asking why did you let him go, but equally I can understand the management team's reasons for doing so.
"They wanted to give him games after his long-term knee injury and it was felt reserve games weren't suitable.
"We had also brought in Philipp Wollscheid to add to the centre-halves we had here.
"The timing was then very unfortunate with the injuries that followed the decision to let Robert go.
"Ryan has got a wonderful appearance record, for instance, but then came that bad run of injuries which included him, Marc Wilson and now Marc Muniesa."
He made his bow for the Foxes by playing the entirety of their 2-1 defeat to Arsenal at the Emirates Stadium last week.
The 30-year-old will hope to do enough during his loan spell at the Premier League's bottom club as he tries to help the side avoid relegation from the division after just the one year in the top flight.
However, the decision to let him leave on loan has received some criticism with Ryan Shawcross, Marc Wilson and Marc Munisea suffering their own injury problems.
Since signing from Middlesbrough, Huth has made a total of 188 appearances for the Potters, so has a wealth of experience playing for the club. Given the need for him to get some game time at the highest level, those at Stoke may be keeping a close eye on his time at the King Power Stadium.