Sunderland have had their fair share of transfer successes and failures in the market over the years with bargain buys and massive flops on Wearside.

Not every transfer is going to work out perfectly with a multitude of factors deciding whether or not a signing ends up being a success; including how they adapt to life in England, how they fit into the team's set-up, how lucky they are with injuries, and how they adapt to a change in management, among other potential stumbling blocks.

One player the club dropped a clanger with was the signing of Jozy Altidore from AZ Alkmaar in the summer of 2013, for a reported fee in the region of £6m.

He was Paulo Di Canio's sixth signing of that window and ended up being a "flop" - as he was dubbed by Sunderland Echo's James Copley - at the Stadium of Light as he struggled at the top end of the pitch.

The forward had arrived at the club after an impressive spell in the Netherlands with Alkmaar. He had scored 51 goals in 93 appearances for the Dutch side prior to joining the Black Cats, including 23 goals in 33 Eredivisie starts in the 2012/13 campaign.

With that eye-catching record, you could forgive Sunderland fans for expecting to see a predatory, clinical, finisher in action on Wearside during the 2013/14 campaign.

Instead, the supporters watched on as Altidore failed to offer much in the way of quality in the final third for Di Canio's side. He ended the season with one goal in 31 Premier League matches, averaging a WhoScored rating of 6.45 - placing him 21st in the squad.

The following season, the 115-cap USA international played 11 matches in the top-flight and was unable to produce a single goal or assist as he averaged a WhoScored rating of 6.15, which placed him 24th (out of 25) in the roster.

His disappointing displays on the pitch led to him being sold to MLS side Toronto in January 2015 and he went on to score 79 goals in 173 matches for the Canadian outfit.

The striker ended his Sunderland career with three goals and eight assists in 52 appearances in all competitions, although only one of those goals and three of those assists came in his 42 Premier League outings.

This means that he cost the club £2m per goal, £6m per league goal, for the £6m they paid to sign him from AZ Alkmaar in the summer of 2013.

Therefore, Di Canio dropped a clanger with the signing of Altidore as he was an expensive flop who failed to deliver on the pitch for the Black Cats, both in terms of the general standard of his performances and his end product.