The England centre will start in this morning's clash with the Melbourne Rebels, two weeks after a shoulder injury forced him out of a tour match against Queensland Reds just 20 minutes in.
Tuilagi has admitted that he is relieved to get another chance to shine after recovering quicker than expected, with the fight on to earn a route into Warren Gatland's Test plans.
He told BBC Sport: "If I'd gone home it would've been the most disappointing thing.
"The Lions doesn't come around very often, and you've got to take your chances. Thank God, the shoulder healed up pretty quick. The physios and the coaches gave me seven days to make the tests to see if my shoulder had any improvement in power.
"Luckily, after a couple of days, it came back 20-25%, which was an improvement, and then they just gave me another week. It feels a lot better now."
The 22-year-old's swift return is a welcome boost for Gatland, with Irish wing Tommy Bowe also back for consideration ahead of the second Test against Australia on Saturday.