Demba Ba was a likable model professional, a useful albeit underutilized striker who graced the Chelsea shirt for a couple years with his flailing limbs, crucial goals, and the uncanny ability to score in the most abstract, awkward ways possible, usually from his backside. He did score arguably the two most famous goals of the second Mourinho era (#6 and #8 in the video below), neither of which resulted in a trophy, but will be forever etched into our (and Steven Gerrard's) memories.
And yet, those two famous goals almost didn't happen at all. And not necessarily because Mourinho kept rotating strikers, looking for one of them to step up and be consistent (neither Torres nor Eto'o nor Ba, in all fairness, managed to do that), but because Ba came just about as close as possible to leaving the club (on loan) in 2013 without actually leaving the club.
"I won't say I regret it, but I think back to the day when Jose (Mourinho) blocked my Chelsea loan at Arsenal. It was the time of his return to the club (note: in 2013). And I think it would have been a very good move (transfer). It happened on the last day of the transfer window. I was in Paris, at rest, and Arsenal representatives called me to tell me it was going to get done. I then returned to London for medical. Upon arriving, I was well surprised that Mr Mourinho had blocked and prevented me from going to Arsenal. Mesut Özil had arrived, and it would've been complicated to over-strengthen a competitor like Arsenal."
"From the perspective of the coach, [I can easily understand the decision], yes. But as a player, you are frustrated."
"Then, the second turning point came when I decided to leave Chelsea for Besiktas (note: in July 2014). A few weeks before, after some crucial goals I scored late in the season at Liverpool, Jose (Mourinho) came to see me to ask me to stay, promising me more playing time next season. But upon returning from vacation, I decided not to follow his request. I thought it was going to probably be like last season ... It turned out that there was only Diego (Costa) and if I had been there I would have actually played more. But choosing Besiktas was one of the biggest decisions of my career, I am proud to have gone there. Of all the clubs where I played, it is number 1 in my heart."
-Demba Ba; source: France Football via Google Translate
Underutilized is sort of the story of Ba's career, both on a national team level (his relationship with the Senegalese national team wasn't always the best) and on a club level, especially at Chelsea. But who knows, perhaps if Ba stays, we never bring back Drogba, and that move turned out to be a decent decision and possibly set the stage for his future involvement in the club, too.
Mourinho of course freely admitted that he blocked Ba's move at the time, and while the player also understood the reasons, with his career-clock ticking, he was looking to be something more than just a backup. Fortunately, he seemed to land quite well on his feet at Besiktas and then he parleyed that one season of success into a big payday in China, which is where he's still playing currently.
So all's well that ends well. (Except our follow-up season to winning the league...)