The Saddlers had already added former Birmingham City and Yeovil winger Wes McDonald and ex-Newcastle United and Blackburn Rovers man Danny Guthrie to their squad as manager Darrell Clarke continues his summer rebuild.
34-year-old Sadler was a league ever-present during his first spell with the Saddlers in 2011/12, scoring one goal in fifty-two appearances in all competitions.
Capped by England at youth level, Sadler started out with hometown club Birmingham City and featured thirty-six times during their 2006/07 Championship promotion-winning campaign.
He made 61 Blues appearances and had a brief spell at Northampton before signing for Watford, where he played thirty-five games.
After loan spells at Stockport and Shrewsbury, Sadler joined the Saddlers in 2011 and stayed for one season before moving to Crawley.
He was an ever-present in each of his two seasons with the Reds and returned to Broadfield Stadium on loan from Rotherham in 2014/15.
Moving to Shrewsbury via a temporary stint at Oldham, Sadler helped Town reach the finals of the League One play-offs and EFL Trophy in 2017/18. He appeared 35 times last season and scored six goals in 161 matches for the Shrews in total.
Walsall manager Darrell Clarke, speaking via iFollow Walsall, welcomed Mat Back to the club, he said; "We’ve been trying to get the right sort of blend with the younger lads in the squad and Mat brings in a lot of experience.
"He’s a leader, was captain of Shrewsbury and led them to the play-offs a couple of seasons ago. He knows the club and what impressed me most was his hungriness; he wants to come here and achieve.
"That’s what I like to see from the older boys; they want to work hard and be part of what we’re trying to build here."
Capped by England at youth level, Sadler started out with hometown club Birmingham City and featured thirty-six times during their 2006/07 Championship promotion-winning campaign.
He made 61 Blues appearances and had a brief spell at Northampton before signing for Watford, where he played thirty-five games.
After loan spells at Stockport and Shrewsbury, Sadler joined the Saddlers in 2011 and stayed for one season before moving to Crawley.
He was an ever-present in each of his two seasons with the Reds and returned to Broadfield Stadium on loan from Rotherham in 2014/15.
Moving to Shrewsbury via a temporary stint at Oldham, Sadler helped Town reach the finals of the League One play-offs and EFL Trophy in 2017/18. He appeared 35 times last season and scored six goals in 161 matches for the Shrews in total.
Walsall manager Darrell Clarke, speaking via iFollow Walsall, welcomed Mat Back to the club, he said; "We’ve been trying to get the right sort of blend with the younger lads in the squad and Mat brings in a lot of experience.
"He’s a leader, was captain of Shrewsbury and led them to the play-offs a couple of seasons ago. He knows the club and what impressed me most was his hungriness; he wants to come here and achieve.
"That’s what I like to see from the older boys; they want to work hard and be part of what we’re trying to build here."