The 27-year-old hasn't played since round 10 last year after he partially tore his achilles tendon at training when he pressing for a return from a four-week hip injury.
He underwent surgery and spent three months in a moon boot.
Recently, Foley ramped up his workload and showed encouraging signs when he ran 20 short sprints at full pace and recorded times similar to those he posted pre-injury.
Coach Damien Hardwick said the club would not be rushed trying to get the ball winner back on the field.
"He's going well. Obviously with the achilles, it does take some time," Hardwick said.
"Whether it's round one or four, we're not quite sure.
"We're in no rush with Nathan, he's an important player for us and we've just got to make sure he gets the stability back in his lower calf and we'll work from there.
"We've got no doubt he'll come back and be a fine contributor for us."
Jake King (knee) and Dylan Grimes (hamstring) are the two other longer-term propositions but both are aiming for the round one clash with Carlton on March 28 at the MCG.
Hardwick said the Tigers' pre-season had been better than previous years as the fitness team had been able to push more work into the players.
"The training age of our team has improved so that means we can get more training into our guys," he said.
"We've had a new fitness regime come in and … we’ve been very pleased with what we've been able to put on the track.
"The thing that has been noticeable is that the boys can handle more work, which is certainly what we needed as compared to last year."
Nathan Foley is a midfielder in NAB AFL Fantasy. He averaged 92.1 points in 2012. Register your team at our AFL Fantasy Hub.
Jennifer Phelan is a reporter for AFL Media. Follow her on Twitter @AFL_JenPhelan.
