McGowan returned on Boxing Day to help Danny Lennon's side to a point at Inverness after an absence of almost three months following a shoulder operation.
St Mirren are back on the road on Sunday when they head to Dundee United and Thompson believes McGowan's creativity can provide the impetus for Buddies to charge up the SPL table.
"He started the game on Tuesday night but he obviously tired as it went on because he has had no football at all," said Thompson.
"He is the player in the team who is on the ball the most during matches.
"He is our creative outlet, a special kind of talent who is capable of winning matches for us.
"There is no doubt that he will need a bit of time to get himself up to speed, but I don't think we can underestimate how important it is for us to have him back in the team.
"Our aim at the start of the season was to push for that top six finish. At the minute it would look as though it's a big ask, but I still think that with a good run we would be able to make it – and having guys like Paul back in the team can only help us with that."
Saints are in the middle of a busy run of games, with two away fixtures followed by a home game against Kilmarnock at New Year before the short winter break beckons.
There won't be a massive amount of down time for the players, but with roughly six days to kick back and recharge, it will be a chance for them to take a breather before the latter half of the campaign kicks in.
"It's not a lot of time but I think players will always welcome a break at this time of year," said Thompson.
"It's a chance to maybe spend a few days not thinking about football and just being with the family.
"But it is also a chance for some of the pitches to get a week to recover because it is hard for them to be at their best at this time of year given the conditions.
"Once you get a bit of time away you tend to come back with a bit more energy and a spring in your step."
Before that, however, Thompson will be back at his old stamping ground at Tannadice on Sunday, a fixture he always enjoys.
"I love playing up there and I still have a real feeling for the club," he said.
"It would be nice to go and get a result that would help us finish the year off on a high."