The 31-year-old has been plagued by injury in recent months, but has now recovered from a hamstring problem to take his place in the 25-man Bath squad named by coaches Mike Foley and Brian Smith.
With Jonathan Humphreys still doubtful for the match after damaging his shoulder in the 30-9 victory over Saracens a fortnight ago, fit-again Andy Long has been drafted into the squad as cover for the Wales international hooker.
Simon Danielli, who scored a brace of tries against Saracens last time out, has had to withdraw through injury allowing Tom Voyce to return to the squad having missed that game at the Rec. There is also a place in the squad for talented No.8 Gareth Delve, who is fit again following knee-reconstruction in the summer. England Under-21 prop Matt Stevens is the other addition to the forwards.
"Catty will be starting, which is great news," said Smith. "He will play in the centre alongside Mike Tindall. In fact, our midfield is the strongest we could field at this time, and is packed with experience. Kevin Maggs will play on the wing, and with Simon Danielli still suffering from a shoulder knock, it is likely that Elvis Seveali'i will start on the other wing.
"It is a different story with Humphreys, though. He has made good progress this week after missing Wales's international last Saturday, but ultimately it will be Chris Mallac's (Head of Physical Preparation) call."
With the two sides have played out an epic Powergen Cup quarter-final at the Rec in January, Smith has the utmost respect for the Saints and believes that his side will have to be at their best to avenge that narrow defeat.
"Northampton have some outstanding players, and I don't think we've played against a better side this season. Matt Dawson is probably the best scrum-half in the world, and their back three of Reihana, Cohen and Beal is just about the best there is. Their forward pack is also immensely strong, so we know we need to put in a big game this weekend."
Bath (squad):Forwards: David Barnes, Andy Beattie, Steve Borthwick, Gareth Delve, Alessio Galasso, Danny Grewcock, Jonathan Humphreys, Andy Lloyd, Andy Long, John Mallett, Lee Mears, James Scaysbrook, Matt Stevens, Nathan Thomas, Adam Vander.
Backs: Olly Barkley, Ross Blake, Mike Catt, Kevin Maggs, Chris Malone, Matt Perry, Elvis Seveali'i, Mike Tindall, Tom Voyce, Andy Williams.
Kick-off: 15.00 GMT