The former Celtic youth scored the decisive goal in Saints' 3-1 win over Kilmarnock, with Conor Newton adding a third after Kris Boyd had cancelled out John McGinn's opener, as Lennon's side rounded off their Clydesdale Bank Premier League campaign with just their third away victory of the season.
But Lennon revealed he has not spoken to the 25-year-old McGowan for weeks and was unsure if the player - who first arrived in Paisley on loan from his old Parkhead employers in 2010 before signing permanently 12 months later - would be staying put.
Lennon said: "It's still in the balance. I haven't had a conversation with the boy for a number of weeks now.
"I opened up talks with him about three months ago and he knows where we stand. I know exactly what his intentions are but we can't wait for ever."
Kilmarnock boss Kenny Shiels did confirm he had won the race to sign the Buddies' Scottish Communities League Cup-winning goalkeeper Craig Samson.
But Lennon has not given up hope of keeping hold of another two heroes from that Hampden victory over Hearts, on-loan Newcastle duo Paul Dummett and Conor Newton.
"The two of them are good players and the boy Dummett just loves defending," said Lennon.
"He's been a pleasure to have. Our club has a reputation now of bringing in players and improving them.
"Newcastle have got to welcome the boys back but we have a very good relationship with them. If they are going to go back out anywhere then I dare say we are in with a good shout."
- Sports & Recreation
- Conor Newton