Supporters began getting excited when the former Republic of Ireland captain was spotted training with the Stags last week and knowing he is without a club.
However, boss Nigel Clough said: “He just did a day with us purely as a favour.
“We know Richard from our Derby days.
“He got in touch through his agent who said Richard is just waiting for a deal at a club and could he come up and do a few days with you.
“That was planned last week but he only ended up doing one and then went off for talks with another club.”